Metal Gear Acid, stylized as METAL GEAR AC!D, is a turn-based collectible card tactical RPG video game developed by Konami Computer Entertainment Japan for the PlayStation Portable. The game was first unveiled at E3 in May 2004, and was released in Japan on December 16, 2004, in North America on March 22, 2005, and in Europe on September 1, 2005. It was a launch title for the PSP, though a Java ME version for mobile phones was released by Glu Mobile in 2008 titled Metal Gear Acid Mobile. Acid focuses on turn-based tactics, using a trading card-based system to control the main character's movements and actions. Acid in the name stands for "Active Command Intelligence Duel". The cards are not truly collectible, as the game is complete with a single purchase. However, the game does feature deck design and deck optimization elements. The game allows for multiplayer gameplay by wireless ad-hoc connections of two PSPs. Gameplay 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 itself. When the game is started, the player's hand can consist of a maximum of six cards. The maximum number of cards in a deck increases with overall progress. In action mode, 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. The lower the cost a character has, the shorter that character must wait until their next turn. For example: if a player character has a cost of 10 and a guard has a cost of 15, then the character's turn would occur before the guard's. Some cards can be equipped; cards such as weapon cards, can have other cards attached to them in order to improve performance.