feature deck design and deck optimization elements.Before each round, the player can customize the deck of cards used by the main characters. The majority of the cards are based upon elements spanning the entire Metal Gear series, such as weaponry, characters, and even the Metal Gear. The player's hand can consist of a maximum of six cards, while the maximum number of cards in a deck increases with overall progress. In action, the player can choose to use the cards as they are intended, or use them to move the character. Most cards only allow the player to move three spaces, while certain cards let the player move up to six or higher.
Cost is an important factor in game play, and can be summed up as the weight of the player's action. With some exceptions, all cards have a cost attached to them, and when used this cost transfers to the player. Cost varies radically from card to card. The higher the cost a character has, the longer that character must wait until their next turn. For example, if a player character has a cost of 15 and a guard has a cost of 10, then the guard's turn would occur before the character's.
Some cards can be equipped, and cards such as weapon cards can have other cards attached to them in order to improve performance. In order to fire the weapon, another weapon card that uses the same kind of ammunition must be equipped. Some weapons don't need to be equipped and can be used by themselves, however they are discarded afterwards. Other cards that can be equipped are equipment cards and action cards.Multiplayer, or "Link Battle", is also a new feature. Two PSP systems running Acid can link wirelessly, allowing players to face each other in a "sneak-off". The objective is to collect a certain number of diskettes before the rival player. Diskettes can be stolen by another player, so there is an emphasis on avoiding detection.
