Carnage Heart (カルネージハート) is a video game for the PlayStation, developed by Artdink. Its gameplay is a mecha-based, turn-based strategy game, where the player takes the role of a commander in a war fought by robots. The robots, called Overkill Engines (OKEs), cannot be directly controlled in battle; they must be programmed beforehand to behave in a certain way under certain conditions using a flow diagram system.
The game also features a fairly complex negotiation system that allows the player to purchase, research, or upgrade new equipment and parts. The OKEs themselves can be upgraded as well through this system, allowing for extended use of the same model for as long as possible. The various companies involved in the negotiation process can also provide valuable information about the purchases of the enemy, allowing the player to better plan for the next advancement in enemy technology.
The main focus of the game is really in the design and programming of the OKEs. The OKEs will only be ready to produce once they have a complete hardware and software profile. Both of these profiles are stored in the form of a "card" that can be named as the player likes. It is possible for there to be a total of 28 cards but in reality the player may use only 25 as there are three pre-made cards that can not be deleted.
Before a software profile can be created for a card, there must be a hardware profile. The first choice a player must make in the hardware creation process is that of a body type and style. There are four styles of OKE bodies and three designs in each style to choose from. These styles include a two-legged type, a tank type, a multi-legged type, and a flying type. After a body has been selected the player then must choose a main weapon, sub-weapon, engine, CPU, fuel tank size, armor thickness, and any optional equipment. A paint scheme may also be applied here as well. The engine determines how much power the robot has, the body type determines how much of that power can be used to haul mass, and all other options are limited by this. Thick armor is very heavy and usually only found on the tank types, since they are very efficient at using engine power to haul mass, while the flying type OKE will require powerful engines just to fly with the thinnest armor in the game. Each component in the hardware profile adds a certain amount of complexity to the OKE; more complex OKEs will take longer to build and require more advanced factories to produce.
Once a hardware profile has been created the player must create a software profile. The player need not have any skill in programming, however, as the game requires no programming in the traditional sense. Instead the player is given a board, which varies in size depending on the CPU selected during the hardware design phase, on which to place chips to act as a set of instructions. These chips must be placed so as to form a flow chart, with control starting from the top-left of the board, following a path through the chips, and looping back to the top left upon leaving the board. Each chip that is available to the player performs a specific task, and many can be edited to allow more precise control over actions. Most of the player's time in the game is spent creating a program and testing it through virtual battle.
The action associated with a chip is performed when control flow reaches it. Actions include simple movements, aim and fire operations, scan for enemy or friendly units, incoming projectile detection, random number generators (to give, for example, a 50% chance of jumping left), variable assignments and checks, and even rudimentary inter-OKE communications, affected by assigning a color to a "channel" which can then be read by other friendly units.
After the OKEs have been set up properly, players must turn their attention to the various bases they control. It is in these bases that the actual OKEs are created, which are then formed into units, each consisting of three OKEs. OKEs are created in the factories on assembly lines that may be upgraded. The number of lines a factory has depends on the size of the base that factory is in. Some OKE designs require the lines to be upgraded in order to produce the advanced technology that the OKE employs. Sometimes a player will need advanced and powerful OKEs, and sometimes it will be more important to be able to produce a lot of OKEs quickly.
Once a player has created OKEs and formed them into units (with a maximum of three OKEs per unit), they may then assign a task to each unit; these include defending or capturing a base, patrolling, or moving to a specific location. When an enemy unit moves into the same space as one of the player's units, combat begins. The combat is carried out entirely based upon the software that was designed for each OKE during the programming phase.
The playing board itself varies in size depending on the mission. Each mission is the same, however, and only the strength of the opponent and the board itself will change. The mission is always to simply capture each enemy base on the map, and it becomes increasingly difficult as the game progresses.
Carnage Heart has had four sequels to date, all of which, aside from EXA have only released in Japan:Carnage Heart EZ ("easy zapping") - an improved version of the original Carnage Heart with additional programming options (macros) and tougher AI opponents. It was released for the Japanese PlayStation Network on March 24, 2009.
Zeus Carnage Heart Second - a sequel with a new storyline, programming was similar but otherwise significantly different from the original Carnage Heart. It was released for the Japanese PlayStation Network on May 13, 2009.
Zeus II Carnage Heart - another sequel (not to be confused with "Zeus Carnage Heart Second") with a new storyline, and vastly improved graphics over the original Carnage Heart. It was released for the Japanese PlayStation Network on June 10, 2009.
Carnage Heart Portable (PSP) - offers improved graphics, updated chips and interface, as well as new OKE types.
Carnage Heart EXA (PSP) - It was released in North America on March 19, 2013