Metal Gear Acid 2 is a turn-based collectible card stealth game developed by Kojima Productions and published by Konami for the PlayStation Portable in 2005. A Java ME version for mobile phones was released by Glu Mobile in 2008 titled Metal Gear Acid 2 Mobile.
Acid 2 is the sequel to the original Metal Gear Acid, with the story set sometime after the events of the previous game. Like its predecessor, it follows an alternate continuity separate from the mainline Metal Gear series. The game uses a completely new cel-shaded graphic engine, replacing the darker graphics from the first game, and features an improved gameplay system. It comes with a PSP add-on called the Solid Eye, which is a folding cardboard box with specialized lenses that fit over the PSP's screen, creating a stereoscopic image.
Gameplay
Gameplay in Metal Gear Acid 2 is similar to that of its predecessor, using a series of collectible trading cards based on the other Metal Gear games. There are new features, such as the SELL option for cards, allowing overstocked cards that the player cannot use to be sold for more points (in-game currency used to buy cards) and cover fire (when a player's ally is behind an enemy and has an equipped weapon in range of the target, when the player attacks, the ally takes a shot onto the target as well). Also added is the ability to move past doors instead of stopping when approaching, and characters can now pick up items such as weapons and card packs by simply running over them (instead of having to end movement on top of the item).
The game uses a revamped engine, featuring a cel-shaded presentation, 3D equipment boxes, and new particle effects. There is a tutorial mode for beginners and a new "Arena" single-player mode that allows players to battle boss characters from previous games, such as Liquid Snake and Vamp, using the Acid 2 card-battling system. There are also extra missions such as "Sneaking" and "Elimination" modes. The game can be also played in the "Wireless Battle" mode (using ad hoc connection only). An additional "Solid Eye Theater" mode allows users to watch videos of the Japanese women seen on posters and magazines throughout the Metal Gear series, utilizing the Solid Eye attachment.
Card system
The gameplay system consists primarily of the usage of cards (obtainable in-game, through a card shop, or other means such as codes or game completion). These cards have a variety of effects for the player, and most can double as a movement card (represented in the form of blocks, referenced as BLKS in-game). Activation conditions include USE (where they can be used immediately if all conditions are met), EQUIP (where cards take up an equipment slot), or MOVE (allowing the player to move). Most cards can move the player three BLKS, but some cards allow more (or less), and a number of cards are dedicated movement cards, most of which are based on soldiers from the previous Metal Gear games. COST is also an important factor, as it affects turn order and is represented in the form of a small counter. It can be summarized as the time taken for the player to perform an action, so if the player has a cost of 0 and an enemy has the cost of 1, the player will go first, regardless of the number of turns the player has had (unless a condition or card effect states otherwise). If the player (or enemy) builds their cost up to the amount that another character already has, that puts that card behind the character with the equal cost in the turn order. COST build up varies by card and is indicated in the upper-right corner of the card.
There are 565 cards, more than twice the number of the original game, including upgradeable cards. Cards vary drastically: some allow the player to attack (Weapon Cards), some provide support such as the ability to dodge an attack (Support Cards), giving the player the ability to perform an action such as the "hold-up" move that incapacitates enemies when the player threatens them from behind or to choke an enemy unconscious (Action Cards), to use items like rations or body armor (Item Cards), or special character cards with varying effects based on the characters they represent (either all from Metal Gear games or other Konami games) such as the Sniper Wolf card with gives the player 40% more accuracy on equipped weapon for one use (Character Cards). Some cards reduce cost or give an extra turns or action points (each card takes up one action point).