The game features most of the best known superheroes from the DC Universe, including Superman, Batman, and Wonder Woman among others. Each level consists of two members of the Justice League battling a variety of villains and their henchmen. When the game is being played by a single player, the player can freely switch between playing as either of the two Justice League members at any time. In a two player game, the players can only switch which characters they control by mutual consent. There was another Justice League game in development from Midway Games that was canceled in 2004 but, according to Warner Bros., this game is totally unrelated to the current project.[3]
Upon starting a new game, the player has immediate access to Superman, Batman, Wonder Woman, The Flash, John Stewart, Martian Manhunter, and Zatanna, but more characters (as well as alternative costumes) can be unlocked as the game progresses. These unlockable characters can only be used on levels in which the player(s) can choose which characters to take whereas the costumes can be used at any time.
There are also initially three difficulties (Easy, Medium, Hard) and then upon completion of Hard, Elite is unlocked, and then upon completion of Elite, Superhero is unlocked. In each successive difficulty level, the opponents do more damage to the superheroes and also have more health/life, offsetting the gains in skills. On Superhero difficulty, many of the opponents will kill most superheroes in one hit, so the player must have mastered a number of skills and strategies to deal with them.