The game received considerable acclaim for its brightly colored graphics, expansive plot, Ring Command menu system, and innovative real-time battle system. Secret of Mana was directed and designed by Koichi Ishii, programmed primarily by Nasir Gebelli, and produced by veteran Square designer Hiromichi Tanaka. An innovative cooperative multiplayer system allows a second or third player to drop in and out of the game at any time. The game has a unique Ring Command menu system, which pauses the action and allows the player to make decisions in the middle of battle. Rather than using a turn-based battle system like contemporaneous role-playing games, Secret of Mana features real-time battles with a power bar mechanic. Set in a high fantasy universe, the game follows three heroes as they attempt to prevent an empire from conquering the world with the power of an ancient flying fortress. It is the sequel to the 1991 game Seiken Densetsu, released in North America as Final Fantasy Adventure and in Europe as Mystic Quest, and it was the first Seiken Densetsu title to be marketed as part of the Mana series rather than the Final Fantasy series. Secret of Mana, originally released in Japan as Seiken Densetsu 2, is a 1993 action role-playing game developed and published by Square (now Square Enix) for the Super Nintendo Entertainment System.