Hearthstone (video game)

Gameplay

Hearthstone is a digital-only collectible card game that revolves around turn-based matches between two opponents using pre-made decks of cards. Players can choose from a number of game modes, with each offering a slightly different experience. Players start the game with a limited collection of basic cards but can gain rarer and more powerful cards through purchasing packs of cards or as rewards from specific game modes. Hearthstone is purposely designed to exclude card trading, while allowing players to disenchant unwanted cards into a quantity of arcane dust that can then be used to craft new cards of the player's choice. Players customize their decks with any gained cards to improve their chances of winning and gaining further rewards.

Hearthstone is free-to-play, only requiring the player to download the game client for their computer or device after setting up a free Battle.net account; supporting the ongoing development of the game comes from micropayments. Players can earn in-game gold by winning play mode matches and completing daily quests, such as winning a certain number of matches while in play mode with a particular hero class. A player can have up to three active daily quests which carry over until completed or the quest is declined by the player then a new daily quest is given once a day. Gold can be used for booster packs, entry tickets for arena and access to adventure wings. Alternatively, players can spend real money to purchase these items directly, and can buy exclusive card-back skins and alternate heroes. Once the upcoming expansion releases in April 2017, Blizzard anticipates adding daily log-in rewards that can include gold, arcane dust for card crafting, and cards and card packs.

Hearthstone is set within the Warcraft universe, with its characters, spells and locations drawing from existing lore.

Matches

Each Hearthstone match is a one-versus-one battle between two opponents. Gameplay in Hearthstone is turn-based, with players taking turns to play cards from their hand, casting spells, equipping weapons, or summoning minions to do battle on their behalf, limited by available mana. Games may be between two players, or one human player and one computer-controlled opponent.

Each player is represented by a 'hero', a character from Warcraft lore representing one of nine specific classes. The classes are defined by their unique hero power that can be used once-per-turn in matches, and the selection of class-specific cards that the player uses to construct the hero's deck. The nine available classes, along with their hero names, are Mage (Jaina Proudmoore, Medivh or Khadgar), Priest (Anduin Wrynn or Tyrande Whisperwind), Warlock (Gul'dan), Paladin (Uther the Lightbringer or Lady Liadrin), Warrior (Garrosh Hellscream or Magni Bronzebeard), Druid (Malfurion Stormrage), Hunter (Rexxar or Alleria Windrunner), Rogue (Valeera Sanguinar) and Shaman (Thrall or Morgl the Oracle). In some of the game modes, such as Adventures or Tavern Brawls, the player may play or face against a non-standard hero or enemy with a pre-built deck and a unique hero power which are not available outside of these game modes.

At the start of the match, each player draws cards from their respective deck of thirty cards after it is shuffled. One player is randomly selected to go first. The first player draws three cards while the second player draws four. Players have the option to mulligan any number of cards and redraw the same number, shuffling the returned cards back into the deck. At the end of the mulligan, the second player gets another card called "The Coin," a card that gives a single use mana crystal at any time. Despite the second player's two card advantage, lead designer Ben Brode claims that on average the first player has a 3% higher chance to win, and Ars Technica's analysis of three professional tournaments found only an insignificant advantage for the first player. Each player subsequently starts with no existing mana crystals.

Players then proceed to alternate turns. At the start of each turn, all empty mana crystals for a player are refilled and they gain a new filled mana crystal, up to a maximum of ten. The player then is required to draw a card from their deck; if they have run out of cards, their hero takes an increasing amount of damage on each successive draw. During their turn, each player may choose to play any of their cards, use their hero power, and direct attacks against the opposing hero and their minions. Nearly all card plays and hero powers cost a number of mana points, and the player must have at least that many filled mana crystals to perform that action, which then drains those crystals until the next turn. Unlike card games like Magic: The Gathering, the opposing player has no means to interrupt or counter the current player's action during their turns, though some card effects can be triggered by the other player's actions and are automatically handled by the game. Each player's turn is limited by a timer, pausing only during card animations; the player is warned when this countdown is nearly over by displaying a burning rope. If the countdown ends before they complete their turn, they forgo any further actions and their turn ends. Players can end their turn at any time before this, and the game will indicate to the player when they have exhausted all possible actions for a turn to allow them to end it early.

Heroes typically start a match with 30 health points. Some cards and hero powers allow the hero to gain a number of points of armor. Any damage to the hero is first taken away from this armor value and it must reach zero before damage can be done to the hero's health. A match is concluded when one or both players have reached zero health, when a player chooses to concede or when the maximum number of turns is reached. Completing a match will grant each player experience for that hero class, with more experience points gained by the winner. Leveling hero classes grants the player access to additional basic cards up to level 10 for that hero or golden versions of Basic cards past level 10; once all heroes are level 60, the player will have all the golden versions of the basic cards.

Each match takes place on a randomly selected battlefield, representing the board on which the game is played. Several of the battlefields are inspired by the lore of Warcraft or based on the game's expansions. Each battlefield features its own design and many interactive elements, but the gameplay is in no way affected or determined by battlefield selection; the differences are purely cosmetic. Around the battlefield are the game's important user interface elements, which are each player's hand, deck, hero's portrait, hero's power, mana crystals, the log of recent cards played and actions taken and each hero's summoned minions. At any time, players can select or mouse-over face-up cards to get more details on their effects including definitions of keywords. The player may use six pre-set emotes to communicate with their opponent. Text-based messages may be exchanged with the opponent if they are part of the player's Battle.net friends list. Players may observe and send messages to their Battle.net friends while the friend is playing a match.

Cards and minions

Cards are the main substance of Hearthstone, representing the abilities, characters and effects which each player is able to make use of during the match. Cards fall into three broad categories: summon cards to bring minions into the game, spell cards that create some type of immediate single-use effect, and equipable weapons that enable the hero character to attack directly. All cards have a mana cost that must be provided by the available mana the player has for that turn.

Once summoned, minion cards each have an attack and a health value; when a minion attacks a target, it will deal its attack value to that target's health, and if it is attacking a minion, it will take damage based on the defending minion's attack value. A minion's health does not regenerate at the start of the player's next turn, so minions can be destroyed after taking smaller amounts of damage over several turns. Minions normally cannot attack the turn they are put into play, and once in play can only attack once per turn. Some keywords affect the behavior of minions from these basic rules: examples include those with "Taunt" that must be targeted before any other minion or the opposing hero can be targeted, and those with "Charge" can attack the turn they are brought into play. Other keywords define actions to be taken at specific events: minions may have "Battlecry" events that only trigger when they are summoned into play and "Deathrattle" events that occur when the minion is killed. Minion positioning on the game board can be important as some minions and spells will affect adjacent minions. Minions may belong to a specific tribe such as "Beast", "Demon", and "Murloc" as labeled on the card. Some cards can be influenced by or can influence minions in play or in the player's hand that belong to that specific tribe.

Spell cards can be used to cause damage to the opposing hero or their minions, heal the player's hero or minions, apply buffs or de-buffs to minions, or draw additional cards from their deck. As a digital-only game, some of Hearthstone's spells can also be used by the player to pull in cards from the entire available Hearthstone library that meet certain requirements, even if they do not own these cards. Spell effects may last for only a turn or may be permanent on the card it affects as long as it stays in play.

Equipable weapons have an attack value and a durability value. When equipped, the player can direct their hero to attack as if they were a minion; the hero's attack value will be that of the weapon, and the hero will take damage if he attacks a minion. The weapon's durability drops by one after the attack, as well as through other card effects, and if it drops to zero, the weapon is destroyed. Usually, weapon attacks can only be used once a turn.

At times, Blizzard has altered the attributes and effects of certain cards after their release based on observations from gameplay, to prevent unforeseen game-breaking combination attacks that would be over-used by players. Many of these changes are "nerfs", reducing the effectiveness of the card's ability, while there have also been some "buffs"/"revamp" that improve cards. These changes are retroactive, affecting all existing cards owned by players.

Decks

In all game modes except Arena and some parts of Adventure mode and the weekly Tavern Brawls, the player does battle using a deck of 30 cards constructed from cards in the player's collection, using any mix of neutral cards available to all classes and specific class-based cards set by the chosen Hero. Each deck can only feature two of each card and only one of each legendary card. Legendary cards are the rarest cards in Hearthstone and are based on special characters that played a role within the Warcraft world. When summoned, Legendary cards will play a special animation or sound and will also have a dragon border around them. Arena play features no such limitations but requires players to play using a new deck chosen from a series of randomly provided selections.

With the introduction of the "Whisper of the Old Gods" expansion, new decks are built either to the Standard or Wild format, and such decks can only be played against a deck of the same format. Wild format decks can use any cards within the Hearthstone library, limited by standard deck construction rules. Alternatively, the Standard format limits cards to those in the Basic and Classic set, and from any newer expansions (those released from a year to two years prior). Older expansions are thus effectively retired from the game overall: cards from previous expansions cannot be used except in Wild formats, nor would card packs or these expansions could be purchased, though players could still craft these cards or complete purchased adventures to own them. The Standard approach was added to help improve competitiveness for new players while helping to maintain a dynamic metagame. Blizzard has adopted a "Year" moniker to help identify what expansions have been retired; the first, "Year of the Kraken", retired the Curse of Naxxramas and Goblins vs. Gnomes expansions, while the upcoming "Year of the Mammoth" will retire the Blackrock Mountain, The Grand Tournament and League of Explorers sets. The "Year of the Mammoth" Standard set will also move some Classic cards to a "Hall of Fame" set that will not be playable in Standard but still can be obtained through card drops and available to play in Wild format.

The construction of a player's deck is a key strategic element in the game, determining which cards are available during a match. The game gives each player a premade deck for each Hero type using the game's Basic cards, allowing them to get a quick start in the game. The game provides a few deck recipes for each hero type that are based on various successful deck archetypes and it populates the deck with the cards a player already owns. Hearthstone offers a deck construction helper to guide new players on selecting a good range of card types and values, or to finish off decks that are partially completed. The player has the ability to create up to 18 custom decks, upped from nine before the release of Whispers of the Old Gods.

Card library and crafting

On release, the game consisted of the same Basic set of cards that all players begin with and earn through leveling up all the individual heroes. All additional cards are generally gained by winning or buying card packs in the game; each card pack consists of five random cards, including at least one card with the rarity Rare or higher. On Hearthstone's release, purchased cards and packs would be from the Classic set, while with the release of each expansion or Adventure, cards and packs from that expansion could also be gained. Reward cards, not considered part of Standard play, are earned by completing meta-game quests within the game such as collecting all the Classic set's Murloc cards. As of August 2016, there are 922 unique collectible cards in the game, with more planned to be added in the future through expansion packs and adventures. Not all cards in the game are collectible in a player's library, as some cards are created as effects from other cards or spells, while others are unique to specific Adventure or Tavern Brawl game modes. The former are comparable to Magic: the Gathering's tokens. Each card is classified as neutral or specific to one of the nine classes; with the introduction of Mean Streets of Gadgetzan, tri-class cards were added, meaning the card can be used by three different classes.

Players can purchase card packs within the game or through the Battle.net storefront. Players can purchase decks from any of the current available expansions for Standard play as well as the Basic set. A single pack costs 100 gold coins (in-game currency); alternatively, players can purchase multiple packs at a time using real-world funds with volume discounts; for example, two packs cost $2.99 (€2.99 or ₤2.99) while 60 packs cost $59.99 (€69.99 or ₤59.99). All cards in a card pack are randomly selected from the given expansion, but one card is guaranteed to be of Rare or higher rarity.

Additionally, players can use the crafting system to create new cards. The system uses arcane dust to craft specific cards. Arcane dust can be obtained by destroying existing cards, from arena mode rewards or from the end of season rewards. Because cards can be used in more than one of the player's constructed decks, a player only needs a maximum of two copies of any regular card or one copy of a legendary card in their collection, and the game can automatically convert extras into arcane dust. The crafting system was created as an alternative to the player card trading prevalent in trading card games such as Magic: The Gathering, with no plans for cards to be traded between players. Like the foils found in physical collectible card games, Hearthstone features golden cards that are special versions of regular cards featuring a golden border and unique animations. These cards are less common than the regular ones and are worth more arcane dust. Golden cards differ from their regular counterparts purely cosmetically and are designed to allow players to show off their special cards to others.

Expansion and Adventures

Blizzard has expanded Hearthstone roughly three times a year by the addition of Expansions and Adventures. Each expansion present more than 100 new cards to Hearthstone developed around a theme or gameplay concept; once released, players can purchase or win card packs with cards from the available expansions to add to their library. Adventures represent fewer new cards, typically a few dozen, which are only gained by winning specially designed matches against computer opponents in the single-player mode. Access to an Adventure requires payment with in-game gold or real-world money. All Adventures released to date have multiple "wings" that must be completed; each wing can be purchased separately for 700 gold or $6.99 (€6.99 or ₤6.99), but plays can also spend real-world funds to get access to all wings at one time with a small discount from buying each individually.

With the "Year of the Mammoth", there will be no Adventure releases, but the game will include freely-available single-player missions, similar to those in Adventure, to earn card packs from that Expansion.

Game modes

Five game modes are available to play in Hearthstone and matches in all modes except for Duels/Solo Adventures counts towards quest completion:

Players can gain a quest daily, and have up to three quests, that can be completed to earn in-game gold or other rewards. The requirements of these quests are based on cumulative performance in matches, typically requiring the player to win multiple matches with certain hero classes, destroy a number of minions, damage opposing heroes, observe a friend winning a game, or other similar tasks. Progress towards completing quests typically can only be achieved through game modes with random matchmaking (Play or Arena), but Blizzard has offered periods where other play modes, such as duels against friends, can count. A player can "reroll" a quest they do not feel they can complete once per day. With the "Year of the Mammoth" introduction, Blizzard plans to add daily log-in rewards and other meta-game elements.

Game regions

Hearthstone offers play in four different geographical regions: Americas, Europe, Asia and China. Players can only compete and communicate with other players within the same region. While each player is by default assigned to a region loosely corresponding to their registered country of residence, players are able to switch regions within the Battle.net launcher, allowing them to play against those of other regions if they wish, although players from other regions are unable to select the China region for play on the same device. Each region holds a separate profile for each player, and it is not possible to transfer cards, gold or other details between regions. Players wishing to play in a new region have to begin the game from the start, including replaying the tutorial and restarting their card collection.

Card sets

The following table lists the card releases by their type or expansion name, their North American date of release (with release in other regions typically with the day or two afterwards), the date of the expansion's removal for purchase (though cards can still be crafted), and the distribution of cards within that release. Blizzard has announced there will be three expansions of about 130 cards each in 2017.

Conception

Development of Hearthstone at Blizzard was inspired by two directions, according to developer Eric Dodds: a desire for Blizzard to develop something more experimental with a smaller team in contrast to their larger projects, and the shared love of collectible card games throughout the company. Blizzard executives, around 2008, had considered that their revenue was primarily sustained on three well-established properties (the Warcraft, StarCraft, and Diablo series), but saw the rise of small independent developers with highly successful projects, representing a shift in the traditional video game model. To explore this new direction, Blizzard brought a number of people into "Team 5", named after being the fifth development team formed at Blizzard. Initially, the team had between 12 and 15 members, in contrast to other Blizzard games with teams in excess of 60 members. By November 2015, the team had 47 members.

Of the game types they explored, Team 5 soon focused on the collectible card game approach, given that many on the team and in Blizzard had played such games since their introduction. The team found it natural to build the card game around the existing Warcraft lore; according to production director Jason Chayes, Warcraft was already a well-known property, and the depth of characters and locations created for other games in that series made it easy to create cards inspired by those. They also saw that new players to Warcraft may be drawn into the other games through playing Hearthstone. The team was able to pull concepts and art from the pre-existing World of Warcraft Trading Card Game, first published in 2006 by Upper Deck and later by Cryptozoic Entertainment; when Hearthstone was near completion, in 2013, Blizzard terminated its license with Cryptozoic as to favor their pending digital card game. The addition of heroes, an aspect from the previous trading card game, was found to help personalize the game for the player to allow players to discover useful combinations of cards for each hero.

Game design and programming

After about a year of starting development, the team had produced an Adobe Flash prototype of the game that offered the core card game mechanics and Heroes. At this point, several on Team 5 were temporarily moved into other teams to complete the release of StarCraft II: Wings of Liberty. This 10-to-11 month period was considered fortuitous by the team, according to Chayes. Principal designers Dodds and Ben Brode remained developing Hearthstone, and the two were able to quickly iterate many ideas using both the prototype and physical replicas to fine-tune the game mechanics. Secondly, those that were put on StarCraft II came back with ideas based on StarCraft's asymmetric gameplay to help balance the various heroes while still creating a unique characterization and play-style for each.

Further development on the game's user interface began using the principle that the game needed to be both accessible and charming, being able to draw in new players and to be clear how to play the game. Unity was used as the game engine in the interest of speed and to make the game run smoother, the server is where all of the rules exist and calculations happen, the server tells the client what happened. Dodds stated that "it's important that you don't have to spend a lot of time understanding the rules to play the game, the depth grows as you go." Gameplay elements such as pre-made decks for each hero, deck building helps, and visual cues on which cards could be played were used to guide new players. Card text was written in a way so that a new player should be able to immediately understand the effects.

From the beginning, the game was designed to be played solely online and to mimic the feel of physical cards, as to make it more accessible to new players. Dodds found that past attempts to digitize physical card games by other companies left areas they felt were lacking, and wanted to improve on that experience. One particular example are card games where players have the ability to react to other players; Dodds noted that when playing in the same room as another player, these types of interactions are straightforward, but consume a great deal of time in a virtual space. Hearthstone was designed to eliminate the reactions from the opponent during the player's turn, streamlining the game.

Other aspects of the game's interface were set to replicate the feel of a physical game being watched by an audience: Hearthstone starts with the player opening a box, during gameplay the cards waver and move while in their hand, and cards when played slam down on the board. When attacking, cards leap across the board to strike the target; when a massive spike of damage is dealt, the board shakes; when a massive creature is summoned, an unseen audience gasps in awe. Hearthstone also offers interactive boards. The boards on which the cards are played can be interacted with in various ways, such as virtually petting a dragon, although the feature is purely for entertainment and has no effect on gameplay. This idea came out from the movie Jumanji in which a board game comes to life, and also mimics how physical card players would often toy with their cards while waiting on their opponent.

Unlike physical trading card games or other digital ones, Hearthstone was designed early on without any trading system between players. Hamilton Chu, executive producer of Hearthstone, stated that "a key thing for us was focusing on [the user]... playing the game", and that trading and market features would dilute this experience. Blizzard wanted to do things such as avoid a free market where card values could fluctuate, discourage cheating methods like bots and duping, reduce the unauthorized third party sales (all against the terms of use), and keep the profit derived from the game for the company.

The game's name, Hearthstone, was meant to imply to a close gathering of friends by a hearth, a goal of what they want players to feel. According to Chayes, they had experimented with other constructs of where these card games would take place, and only about halfway through development came onto the idea of using a pub's hearth as the theme; Chayes stated that with that concept, "this is a great way to play, it works with all our values, it has a lot of charm". To maintain a friendly environment around this construct, they added in the ability to trigger one of a few friendly compliments said by the Hero, so that players could still emote to their opponent without having to worry about any vitriol.

Soundtrack

The soundtrack was composed by Peter McConnell; with trailer music by Jason Hayes. According to McConnell and Dodds, who oversaw the music direction, they wanted to create a soundtrack that would reflect the tavern setting they had established for the game, but they did not want to overwhelm this theme. McConnell came upon the idea of mixing Celtic music with blues rock—pondering the idea of "what if ZZ Top or Golden Earring had been transported back in time to the Middle Ages?"—and working in other previous Warcraft themes among the new songs with help from Hayes. Hayes also worked with Glenn Stafford to create short "stingers" of music used when players summon Legendary cards.

Promotion and release

Internal beta testing of the game within Blizzard began in 2012. A closed beta was launched in August 2013, while the game was put into open beta in January 2014. These beta testing periods were used to evaluate the game's balance, adjusting cards they found to be too powerful or too weak, and making sure no single Hero or deck type dominated the game. As they approached the game's release in March 2014, Blizzard found that it was hard to generate interest in getting people to try the game, believing that once they tried it they would be drawn into the game; those they asked to try the game felt that Hearthstone wasn't the type of game they would be interested in playing. At this point, Blizzard opted to make Hearthstone free to play supported by microtransactions for less patient players. This helped to significantly boost the game's popularity on release.

Ongoing support

Blizzard provides regular bug fixes, updates, and expansions for Hearthstone. Hamilton Chu, the executive producer for Hearthstone, stated that Blizzard intends to support the game for ten to twenty years, similar to Blizzard's other titles, though they have no long-term plan of how they would continue to introduce cards. The principle means that additional cards have been introduced to the game are through either themed Expansions or Adventures. Expansions are new card sets, containing between 100-200 new cards, that become available to buy or win, as well introducing new mechanics to the gameplay. Adventures feature smaller number of cards, between 20-45, which can only be earned by completing multiple tiers of story-based challenges and boss fights in single player mode. Blizzard had originally envisioned to release Expansions in a staged approach as to not drastically jar the player community, creating the Adventure concept for the first post-release addition with "Curse of Naxxramas". By the meta-game remained unpredictable both during and for several months, helping to keep the playing community interested in the game and validating their approaches. The solo challenges on Adventure mode also served as a means to help players understand some of the stronger archetypes of card decks and learn strategies to defeat them, helping them become better players against human opponents. Going forward in 2017 in the "Year of the Mammoth", future expansions will principally be around the new cards sets, forgoing Adventures. Blizzard recognized that players do enjoy the single-player narrative events and will work in quests and missions around the new card sets for those players.

Development of the themes and mechanics for each Expansion and Adventure are often based on the current atmosphere around the Hearthstone community, according to senior designer Mike Donais. While early expansions were based on the Warcraft franchise, the developers have been able to move away from staying with that narrative and are free to create new aspects not established by Warcraft. This idea was reflected by the dropping of the "Heroes of Warcraft" subtitle from the game's name around December 2016 to demonstrate to new players that the game was no longer tied to Warcraft.

In addition to new cards and mechanics, Blizzard has also worked to add new features to Hearthstone itself. The Tavern Brawl mode was in development for over a year before it was released in June 2015; the feature went through many iterations before the team was satisfied. Dodds equated the Tavern Brawl mode as a place to try experimental mechanics that may later be introduced to the game, as well as to offer gameplay that varies significantly from other areas of play within Hearthstone. Blizzard experimented with cross-platform play during development, having successfully played a game on PC against a player using an iPad; however, it was not a feature at launch. Cross-platform play was added in April 2014.

The introduction of the Standard vs. Wild formats in April 2016 was an issue that the developers knew since Hearthstone's initial release that they would need to address; according to Brode, as new cards were introduced to the game, they recognized that new players would start to find the game inaccessible, while adjusting the balance of the meta-game of which cards from previous expansions had proven over- or underused. The ideas for how to actually implement Standard mode started about a year before its introduction. Though they will continue to design the game to maintain the appropriate balance for the Standard format, they will also monitor how future cards will impact the Wild format and make necessary changes to keep that mode entertaining. With the upcoming Year of the Mammoth changes to Standard, the designers opted to move some Classic cards to a new Hall of Fame set that would not be usable in Standard. They found that these cards were often "auto-includes" for certain deck types, and created a stagnant metagame around those decks, and opted to move them out of Standard. As compensation, those that own these Hall of Fame cards will receive the arcane dust value of the cards they possess while being able to use those cards in Wild play format. The "Hall of Fame" format would also allow Blizzard to move Classic cards that have been "nerfed" (purposely weakened) previously to be un-nerfed and moved into the "Hall of Fame"; Blizzard found that players using Wild decks were impacted significantly by these nerfs and this approach would allow those deck formats to still thrive without disrupting Standard play. To make up for cards moving out of Classic, Blizzard may consider bringing in individual cards from already-retired sets into the Classic set that they believe would be suitable for Standard format. The associated switch of Arena mode from Wild to Standard with modified card rarity distributions with the "Year of the Mammoth" update was aimed to keep the pool of cards available to draft smaller, increasing the chances of drafting cards that they had intended to be used in synergistic combinations from the individual expansions.

Release

Hearthstone was first announced at Penny Arcade Expo in March 2013 for Windows, Mac, and iPad, with an expected release date in the same year. In August 2013, the game went into closed beta, to which over one million players had been invited as of November 8, 2013, with plans to enter open beta in December. Blizzard continued closed beta into mid-January 2014 despite their original estimation. Blizzard announced open beta for North America on January 21, 2014. Open beta was announced for Europe on January 22, 2014 and on January 23, 2014 open beta was made available in all regions.

The game was released on March 11, 2014, available on Microsoft Windows and OS X operating systems. By the end of March 2014, the game had more than 10 million player accounts registered worldwide. On April 2, 2014, the game was released for iPad in Australia, Canada and New Zealand. On April 16, 2014 it was released globally, supporting all iPads except the first iPad. On August 6, 2014, support for Windows 8 touchscreen devices was added to the game, although not for Windows RT devices. On December 15, 2014, the game was released for Android tablets 6" or larger in Australia, Canada and New Zealand and on December 16, 2014 it was widely released for Android tablets. On April 14, 2015, the game was released for iPhone and Android smartphones worldwide. The smartphone version of the game includes new UI elements that place the player's hand on the bottom right but only half visible, so players must tap on their hand to zoom in and play cards. Single cards can also be viewed full screen by tapping and holding on a specific card, which is useful to read all the card details while using a smartphone display.

Expansions

To date, there has been eight Expansions and Adventures as of December 2016, with one expansion due in April 2017 and two more by the end of 2017.

The Adventure "Curse of Naxxramas" was announced on April 11, 2014, and then was released on July 22. It includes 15 bosses and nine class challenges that together awards 30 cards, which includes six legendaries, and an exclusive card back if all heroic bosses are defeated. "Curse of Naxxramas" was developed to focus on a specific gameplay mechanic, with the team settling onto exploring the design space around the "deathrattle" keyword. This led to the narrative of the player having to explore a location filled with ghosts and undead creatures as to take advantage of deathrattle effects. As it was a single-player Adventure, the team also developed bosses that would be far different from typical human opponents, including some boss characters that would break the fundamental rules of the game. Lead artist Ben Thompson said that they made it felt like winning against these bosses was something that the player earned, as well as helping the player to learn new tricks they could use in regular play modes.

The Expansion "Goblins vs. Gnomes", was announced at BlizzCon on November 7, 2014, and then it was released on December 8. The expansion includes 123 cards from its specific card pack. Pricing for the packs are the same as Classic packs. "Goblins vs Gnomes" was the first large Expansion, and rather than roll out cards as they did with "Curse of Naxxmasas", they felt their goal with this "was ‘let’s make a bunch of cards that will really go in and just blow up the meta all at once,’ and we’ll see how it goes, and maybe that’ll affect how we do things in the future," according to Chu. A central theme was designed around "Mech" cards which would interact with cards that represented goblins and gnomes.

The Adventure "Blackrock Mountain" was announced at Pax East on March 6, 2015 and the first wing was released on April 2; the other four wings were opened weekly thereafter. It includes 17 bosses and nine class challenges that together awards 31 cards, which includes five legendary cards, and an exclusive card back if all heroic bosses are defeated. "Blackrock Mountain" was designed as to help support players that wanted to construct dragon-themed decks. Dragon cards in Hearthstone are generally expensive to cast and thus only appear in the latter part of a match, making such decks weaker in the opening rounds. With "Blackrock Mountain", the team introduced cards that interacted with dragon cards, such as by having buffs when summoned for having a dragon card in hand, or helping to provide mana to summon a dragon faster.

The Expansion "The Grand Tournament" was announced on July 22, 2015, and was released on August 24; the set includes 132 cards from its specific card pack, which costs the same as previous card packs. "The Grand Tournament" was developed with a new card mechanic for minions called "Joust" which has combat between a minion with Joust with other minions based on the casting cost of the minions, rather than their attack and health. Donais noted that while this also created a central theme for "The Grand Tournament" expansion, it also served to help combat "aggro" decks—decks filled with low-cost minions that could be quickly deployed—which at the time of the expansion's release, were extremely popular and found to be discouraging to many players. "The Grand Tournament" also introduced the "Inspire" mechanic for minions, which would create some effect for the minion each time the player used their Hero power, often including cumulative effects over several turns. Donais said the Inspire keyword came about looking at how to interact with Hero powers better, and while Inspire-based cards could be slow and at risk, could have great payoffs if used properly.

The Adventure "League of Explorers" was announced at BlizzCon 2015 on November 6, 2015, and the first wing was released on November 12; the other three wings were opened weekly with a week-long break after the second wing. It includes 13 bosses and nine class challenges that together awards 45 cards, which includes five legendaries, and an exclusive card back if all heroic bosses are defeated. "League of Explorers" was the team's first attempt to craft a narrative that allowed Hearthstone to stand on its own from the Warcraft universe even though it may still borrow concepts from it from time to time. The Adventure borrows from dungeons in desert locations within World of Warcraft but transform the experience to be one of an adventuring archaeologist, and the challenges were more themed around puzzles and traps that the dungeons would present rather than just boss characters. Central to "League of Explores" was the new "Discover" mechanic, which when activated would have the game randomly select up to three cards with specific characteristics from all available game cards, allowing them to select one card to put into their hand. This mechanic was introduced to provide contrast to decks that focused on card draws, which they found out tend to be played in the same manner over time. The Discover mechanic allowed decks to be more random but provide some player decision for on-the-spot judgement calls depending on the situation.

The Expansion "Whispers of the Old Gods" was announced on March 11, 2016, and was released on April 26; the set includes 134 cards from the its specific card pack, which costs the same as previous card packs. "Whispers of the Old Gods" was based on creating a theme around mysterious and dark Lovecraftian horror, such as Cthulhu, to contrast to the high adventure and excitement that they had designed with "League of Explorers". This concept of crafting powerful god-like characters let them brainstorm on wild ideas for cards that may seem overpowered for the game but that would fit the theme. Central to the expansion is the Legendary "C'Thun" Old God card, which can be buffed by effects from sixteen other cards, disciples of C'Thun, that were part of the expansion, regardless of where the C'Thun card was currently at. Donais explained this helped to create a "sense of dread" in opponents that fit the theme they wanted. Because of this, all players received the C'Thun card and one of the disciple cards for free once this expansion was released. "Whispers" also allowed the designers to take old favorite cards and make "corrupted" versions of them within the flavor of the theme.

The Adventure "One Night in Karazhan" was announced on July 29, 2016, and the first wing was released on August 11; the other three wings were opened weekly thereafter. There are four wings along with a free prologue mission that awards two cards. Kara includes 13 bosses and nine class challenges that together awards 45 cards, which includes five legendaries, and an exclusive card back if all heroic bosses are defeated. "One Night in Karazhan" is based on a popular game location in World of Warcraft, featuring an abandoned mage's tower that is often used for a dungeon raid. The Adventure features eleven boss characters that are also in the World of Warcraft raid of the tower. The team had designed the concept of this expansion alongside "Curse of Naxxramas" early in Hearthstone's post-release and was considered to be their first adventure, but they ultimately used Naxxramas, as Karazhan was being used for other activities by teams within Blizzard at that time. Instead, when they looked towards designing it, they found Priest decks had difficulty in staying current with the meta-game, so several of the cards introduced with this set were to help make the Priest a more viable class with the shifts in popular decks.

The Expansion "Mean Streets of Gadgetzan" was announced at BlizzCon 2016 on November 4, 2016, and was released on December 1; the set includes 132 cards from its specific card packs. On the day of release, a bug was discovered resulting in "tri-class" cards being unpacked more than others. A hotfix was released a few hours later and players whom had already unpacked cards received 33% compensation. "Mean Streets of Gadgetzan" was originally envisioned to have the spirit of "cops and robbers", according to designer Matt Place and art director Ben Thompson, but the idea transformed into squarely focusing on the crime aspects, and treating the narrative as three principle mafia-like crime families vying for control of the city of Gadgetzan along with a number of small-time criminals that work as hired hands. The nine hero archtypes were divided into sets of three that each worked for a different family, which led to the creation of tri-class specific cards. Each of the three families were given a central mechanic theme: the Grimy Goons would buff cards not yet in play, the Jade Lotus would improve other Jade Lotus cards the more they were played, and the Kabal would allow the player to gain more casting mana but at some cost. They considered introducing a mechanic where the Legendary cards, representing the bosses of each family, would have decreasing casting cost if players used other cards that fed into these family mechanics, but ultimately decided to keep their casting costs lower so these family abilities would be more available to play.

The Expansion "Journey to Un'goro" was announced on February 27, 2017, and expected to be released in April 2017; it will contain 130 new cards from its specific card pack and will be the first Expansion to offer single-player quests, similar to Adventures, to earn card packs and other rewards. "Journey to Un'goro" is based around a pre-historic theme and introduces dinosaurs and a new Elemental tribe, among other creatures. It introduces Legendary cards with the "Quest" keyword that, if the player completes the requirements of the quest, gains a reward offered by the quest, such as summoning in a specific minion. Any Quest cards in the player's deck will be put into the player's opening hand but must be put into play before the player can start completion of that quest. The expansion also adds the "Adapt" keyword to some minions, which allows the player to select a buff that the minion gets when it is put into play.

Promotions

To mark the release of Hearthstone, Blizzard released the Hearthsteed mount for World of Warcraft players that is obtained by winning three games in Arena or Play mode. Widely advertised on various World of Warcraft websites, this promotion encourages World of Warcraft players to try Hearthstone, and marked the first significant crossover implemented between Blizzard games.

Players who purchased the Diablo III: Reaper of Souls expansion pack received Classic packs, with the deluxe and collector's editions granting additional packs. Players who purchased World of Warcraft: Warlords of Draenor Collector's or Digital Deluxe Edition received an Orc handiwork themed card back. Heroes of the Storm players who reach level 12 receive a Heroes of the Storm themed card back and after winning 100 Play mode matches receive a Heroes of the Storm mount that looks like a flying card. Players who purchase the StarCraft II: Legacy of the Void deluxe or collector's editions receive a Protoss themed card back. Players who purchased either Overwatch Collector's or Origins Edition receive an Overwatch themed card back. Starting on March 11, 2016, players who level a character to 20 in World of Warcraft, which can be completed with the free starter edition, earn the alternate Paladin hero Lady Liadrin. An alternate hero for Shaman, named Morgle the Oracle, is available through the game's "Recruit A Friend" program. It is obtained when the recruited user reaches a total of level 20 across all of the heroes. Players that connect their Amazon Prime subscription to Twitch Prime will earn the alternate Priest hero Tyrande Whisperwind.

Players that pre-ordered with real money the Blackrock Mountain adventure received a card back, and players that pre-ordered 50 card packs of the The Grand Tournament or Whispers of the Old Gods received a card back. Players that purchased the One Night in Karazhan adventure with real money within its first week received an exclusive card back.

Competitions

Despite the designers' focus on accessibility and fast-paced gameplay, Hearthstone has been the focus of a number of tournaments. Blizzard hosted an exhibition tournament in November 2013 called "The Innkeeper's Invitational" with three decks each of a different class, featuring several well-known gamers such as Dan "Artosis" Stemkoski, Octavian "Kripparrian" Morosan, Jeffrey "TrumpSC" Shih and World of Warcraft multiple Arena season winner Byron "Reckful" Bernstein. Artosis won the best-of-five tournament. In December 2013, 2P Entertainment hosted a tournament with a prize pool US$4,841 featuring the best players of the Chinese region versus the best players of the American region. Hearthstone was the focus of a number of other tournaments during its closed beta, including those hosted by Major League Gaming and ESL. In March 2014, The eSports Association TeSPA announced the Collegiate Hearthstone Open, a free-to-enter tournament open to all North American college students, featuring $5,000 in scholarships. Major League Gaming, ESL and the ZOTAC Cup all continue to regularly host minor Hearthstone leagues in the North American and European territories with small or no prize pools aimed at everyday players. Blizzard staff "were a little surprised, in a good way" with the game's success as an eSport during its closed beta.

In April 2014, Blizzard announced the first Hearthstone World Championship would be held at BlizzCon on November 7–8. The tournament featured players from each of the game's four regions, with each region holding its own regional qualifying tournament. The Americas and Europe regions' qualifiers featured 160 players each, and determined half of those players from actual in-game performance in Ranked play during the April–August seasons. The four most successful participants of each region's qualifiers went to the World Championship, for a total of 16 players. The Hearthstone World Championship 2014 featured a total prize pool of $250,000, and the American winner, James "Firebat" Kostesich, received $100,000.

The second Hearthstone World Championship was held at BlizzCon 2015 on November 7 with players selected in a similar way in the previous year and it was played in the best-of-five conquest format; the Swedish winner, Sebastian "Ostkaka" Engwall, received $100,000.

The third Hearthstone World Championship was held at BlizzCon 2016 on November 5 and the winner was Russian Pavel "Pavel" Beltiukov, who earned $250,000. It was played in a Swiss tournament format and one class could be banned from using by one's opponent.

The 2017 world champion will earn $1 million.

Critical response

Hearthstone: Heroes of Warcraft received "universal acclaim" on iOS and "generally favorable" reviews for PC, according to review aggregator Metacritic. The game was praised for its simplicity, gameplay pace, and attention to detail along with being free-to-play, while the lack of actual card trading between players and any form of tournament mode were pointed out as the major shortcomings. Eurogamer gave the game the perfect score of 10 and remarked that the game is "overflowing with character and imagination, feeds off and fuels a vibrant community of players and performers, and it only stands to improve as Blizzard introduces new features, an iPad version and expansions." IGN and Game Informer both gave the game a slightly lower grade of 9/10, with IGN's Justin Davis praising the game for its "elegant simplicity of rules" and "impressive attention to detail and personality, and the true viability of playing completely for free make it easy to fall under its spell and get blissfully lost in the depths of its strategic possibilities." GameSpot gave the game a score of 8/10, praising the game for its depth and complexity. The only major drawback noted was that the "absence of extra features hampers long-term appeal".

Later Hearthstone card expansions have also been well received. Game Informer rated the Curse of Naxxramas expansion 9/10, stating "Naxxramas is an excellent addition to the core game, and an exploration of sorts to examine the potential for additional single-player Hearthstone content [...] the adventure provides a substantial amount of new content that spills over into ranked, casual, and arena mode and changes how you approach the game." PC Gamer found that "[Curse of Naxxramas is] a much-needed and fun refresher for Blizzard’s card battler", however "the next card expansion will need to be more sizeable", rating it 78/100. Reception for Goblins vs. Gnomes has also been positive, with Game Informer writing "the first expansion set for Hearthstone is a major step forward for the already accessible and fun game", and awarding it a score of 9.25/10, while Eurogamer scored it an 8/10, writing "whatever happens to Hearthstone in the future, the new content has stumbled a little by strengthening certain deck archetypes that needed no such help [...] it's re-introduced a thoughtfulness to play that's been absent for too long."

Sales and playerbase

By September 2014, there were more than 20 million registered Hearthstone accounts. By January 2015, there were more than 25 million registered Hearthstone accounts. On May 6, 2015, Activision Blizzard announced that Hearthstone and Destiny have generated nearly one billion US dollars in revenue for the company. As of June 2015, the active players consist of about eight million PC players and nine million mobile device players, with some overlap between each group. As of April 2016, Blizzard has reported more than 50 million unique Hearthstone players; the company previously reported 30 million users in May 2015 and 40 million in November 2015. According to Superdata market research, as of June 2015 Hearthstone takes in about $20 million in revenue per month.

Hearthstone proved to be a popular game to stream and watch on services like Twitch.tv; Hearthstone-based streams overtook Dota 2 streams to become the third-most watched game on the platform in September 2015, and remained one of the top five watched games by April 2016.

Awards

Forbes awarded Hearthstone as the best digital card game of 2013. At The Game Awards 2014, Hearthstone was awarded best mobile/handheld game. In December 2014, GameSpot awarded Hearthstone with mobile game of the year. GameTrailers awarded Hearthstone with multiplayer game of the year and best overall game of 2014. At the DICE Awards 2014, Hearthstone was awarded with mobile game of the year and strategy/simulation game of the year. At the 2014 BAFTA Awards, Hearthstone won best multiplayer game. At the 2014 NAVGTR Awards Hearstone won the Game, Strategy (Dan Elggren) award.