Metal Gear Acid 2 (rendered METAL GEAR AC!D² on the official logo, abbreviated MGA2) is a video game developed by Kojima Productions and published by Konami for the PlayStation Portable. It was directed by Shinta Nojiri and produced by Noriaki Okamura and Hideo Kojima. As a sequel to Metal Gear Acid, it establishes the Acid games as a separate franchise from the main Metal Gear series. Metal Gear Acid 2 uses the same turn-based strategy and trading card-based system as the original Metal Gear Acid. The presence of the superscripted "2" in the game's logo is a reference to the upgradeable card system which results in more than twice the number of cards in the original game. As in the first game, ACID stands for "Active Command Intelligence Duel."