Cheats > Game > Cheat: 33630

Extra arena (Power Stone)
The following trick allows the arena that you can play in one player mode to be used in two player mode. Begin a game in two player mode, then hold A + B + X + Y and press Start at the end of the match. Select two player mode again and have either player select Gunrock as a fighter. Immediately press A at the stage selection screen to select the extra arena.