Icy Tower

Gameplay

The player starts the game on the tower's ground floor. To climb the tower, the player must jump from floor to floor (default control: spacebar). The character can pass through the floors from below but lands on them when falling from above. Once the player has landed on a floor, he can move across its surface using the arrow keys. By moving across the floor, the player builds momentum for the next jump. The character can also bounce off the vertical walls on the left and right edges of the tower, allowing them to switch direction while maintaining momentum.

If a player builds enough momentum, he can climb several floors in a single jump. Extended sequences of such multi-floor jumps are referred to as combos. A combo ends when a player makes a jump which covers only one floor, falls off a floor and lands on a lower floor, or fails to make a jump within a certain time frame (about 3 seconds).

At the start of the game, the tower's floors are stationary. When the player reaches floor 5, the floors begin to move slowly downward. Every thirty seconds, the floors's downward speed increases and the game tells the player to "Hurry up!" If the player misses a floor and falls off the bottom of the screen, the game ends. It also ends if the player is standing on a floor that moves off the bottom of the screen.

The goal is to reach the highest possible floor and accumulate the greatest number of points. Points are awarded based on the highest floor reached and the player's combos (if any).

Because the tower is of infinite height, it is impossible to reach the top floor. When the game ends, a replay of the game may be saved for later viewing.

Floors

The horizontal length of each floor depends on the player's progress, the version of the game, and a random factor. The floors's appearances change every 100 floors until floor 1000.

High scores

Icy Tower records players's best results in built-in high-score tables. Scores are recorded in several categories including highest score, highest floor, and longest combo. Players may also publish their scores online high score lists. Online high-score lists may require players to provide game replays to verify their results. The official Icy Tower list resides on Free Lunch Design's web server.

It is also possible to compare two players's performances using the so-called K+ method—a product of a sum of quotients where the divisors and dividends represent records of both players in a specific Icy Tower category. For example, the K+ value from Score, Floor and Combo is represented by the expression

100 [ S c o r e a S c o r e b + 2 ( F l o o r a F l o o r b ) + C o m b o a C o m b o b ] 4 ,

where S c o r e , F l o o r and C o m b o stand for the highest score, highest floor, and longest combo, respectively ( a and b standing for the players being compared). The K+ mechanism is often used in online high-score lists.

History

Free Lunch Design created Icy Tower using the C programming language and the Allegro game library. Its designers were inspired by Xjump, a game for the Linux operating system.

The game follows a sequence-based software versioning scheme. The current version is 1.5. Changes in the minor number denote the entire package of the game being changed, including its sound and graphic resources. Changes in the release number denote a release of a patch, i.e. a modified executable file to fix bugs in previous versions. Patches for Icy Tower are distributed inside and outside of official game packages.

The makers of Icy Tower maintain contact with its players, whose opinions are taken into account in the course of the game's continuing developing. The list of the most significant changes made to it to date includes:

Records file (1.1) 

An automatically generated and updated binary file that contained data about the player's records at a given time. It could be subsequently submitted to the then official online high score list.

Replay files (1.2) 

Small binary files that contain the recording of a given Icy Tower game and the nickname of its maker. Replays are less prone to cheating by manually modifying them than were files used to store players' records in Icy Tower 1.1. Replay saving and viewing features were being improved concurrently with the entire program. For example, replays have since been made easier to sign (1.2.1) and rewind (1.3), as well as possible to sort by various criteria (1.3). It has also become possible to view a progress bar of their duration, their maker's nickname and the arrangement of keys pressed during their making when watching them (1.3) and to save them automatically whenever a player beats his personal record (1.4).

Configurable keyboard settings (1.2) 

The possibility to personalise keyboard keys responsible for the character's movements in the tower. Since Icy Tower 1.3 it is also possible to customise the key pausing the game.

Shortened floors (1.3) 

This change was introduced in order to make gameplay over the 1000th floor barrier more difficult. In Icy Tower versions prior to 1.3 a sufficiently skilled player was able to casually climb as much as several thousand floors, even at the fastest rate of the downward movement of the screen. This was undesirable, as replays from such games often lasted several minutes or more.

Removal of the immaterial floors bug (1.3) 

This bug, known as the "ghost floor" bug, was a collision detection glitch that occasionally caused random floors in the tower not to stop the character falling onto them, usually ending the game as a result. It had only been occurring at the highest game speed and caused several players to quit playing altogether. It was the primary reason behind the making of Icy Tower 1.3. Its creators originally only intended to fix the bug in question in it, release the new version as Icy Tower 1.2.2 and distribute it as a patch.

Player profiles (1.4) 

A concept of user accounts (profiles) was introduced in order to help several players play a single instance of the game. A profile contains certain publicly accessible data about the achievements of its owner (their average and best scores in the game, for example), as well as their personal game settings and preferences. The default profile is the so-called guest profile.

Support for secondary categories (1.4) 

A possibility to manually change default game gravity and speed and default floors length was introduced (this change emulated – to a limited degree – features and options that were previously available for players only by the means of special trainers). Results achieved in the environment modified in such manner do not, however, affect the state of the built-in high score lists, which only register results recorded in default conditions. The categorial scope of the built-in lists was nevertheless expanded; since Icy Tower 1.4 they also register scores in categories formerly considered secondary (such as JS or CC).

Measures against slowdown (1.4) 

Icy Tower 1.4 estimates the possibility that the player's computer was artificially slowed down and records results of this estimation in replay files. A standalone program named SDbuster (Slowdown Buster) was also created in 2007 to help detect slowed down replays, which calculates the possibility of a given replay being slowed down based on previously remembered differences between replays recorded in normal and reduced speed.

Lesser changes include an audiovisual overhaul of the game (1.4, 1.5), the ability to choose the default floor type of the game (1.2) and the ability to create custom game characters (1.2). Four new combo rewards were also introduced: Super!, Fantastic!, Splendid! and No way!, and thresholds of combo length for certain rewards were increased (1.2).

Ports

On March 14, 2007, a press release was published on the Free Lunch Design website announcing a partnership between FLD and mobile game developer Xendex Entertainment for the porting of Icy Tower to the mobile environment. Icy Tower Mobile (ITM) was released on October 6, 2008. Due to the then-current limitations of mobile platforms, the game lacked several features in its PC counterpart, such as recording or sharing replays, and changing game characters.

On September 24, 2009, a Free Lunch Design game named Icy Tower Facebook (ITFB), developed on the Adobe Flash platform within the development framework of the Facebook social networking website, was released. It allows players to compare their results with results of their friends within the Facebook system. Players can also personalise their in-game avatars and unlock additional game levels (so-called towers) corresponding to various game styles in the PC version of Icy Tower by exchanging them for coins, the game's virtual currency.

On November 2012, an official continuation of Icy Tower, Icy Tower 2, was released for iOS and Android. The producer estimates that on November 23, 2012, the number downloads of Icy Tower 2 downloads surpassed one million. There are also unofficial, player-developed Icy Tower ports for the Nintendo DS and PlayStation Portable game consoles.

Reception

Icy Tower ranked high in the "Most Popular" ranking of the "PC games" section in the Download.com software directory website; its average monthly number of downloads was "more than 20,000" in 2006, amounting to over five million as of 2009. The total number of Icy Tower downloads was estimated at over 11 million in 2008. In terms of the number of websites devoted to the game, it is most popular in Czech Republic, Germany and Poland. Central European countries are also home to a major portion of top Icy Tower players. According to Johan Peitz, the author of the game, the reason behind the popularity of Icy Tower is that it allows players to compete in several different categories, for example in striving for both high floors and high scores.

Online Icy Tower communities allow their members to exchange high scores, replays and comments about the game and its gameplay. Additionally, players frequently compete against themselves in online competitions. Icy Tower tournaments usually consist of a number of rounds, each lasting one or more days. In every round, contestants are required to record one or more replays with a result in a specific category of the game. Players have also organized live meetings, which took place in Cracow and Warsaw, Poland and Prague, Czech Republic.

On May 30, 2007, an official Icy Tower website operated by Free Lunch Design was launched, available at icytower.­freelunchdesign.­com. On June 3, 2009, the day of Icy Tower 1.4 release, an additional, complementary site has been opened at icytower.com.

Add-ons

Internal structure of Icy Tower allows for the use of skins through downloading and installation repackaged resource files.

Since the version 1.2 Icy Tower allows players to create additional custom characters which may replace the three default characters provided in the game package. Making a new character only requires the player to create an image file of a certain structure. It is possible, however, to also create more complex ones, using which will cause the game to modify its soundtrack and colour palette.

There also exists an array of tools that assist players in training, changing the game physics or analysing their results.