X-Men Mutant Academy 2
Play as Psylocke:
Beat the game with Wolverine in arcade mode to unlock Psylocke.
Play as Juggernaut:
Beat the game using all default characters and Psylocke in arcade mode to unlock
Play as Professor Xavier:
Beat the game with Juggernaut. Then, highlight Magneto and hold L1 at the character
Play as Spider-Man:
Fight in arcade mode until you face Spider-Man. Defeat him and finish arcade
mode. Then, highlight Cyclops and hold L1 at the character selection screen.
Play through academy mode with any character to get that characters alternate
costume. When you choose your guy hold R1 and press square if they were in the
first game, If they weren't hold R1 and press X.
At the title screen press select, down, R2, L1, R1, L2 This will unlock everything
Put in the unlock everything cheat and then in 2 player you can go to the Pool
Party as your stage. Everyone is equiped with a funny costume.
Thanks to Revolution readers marc aguihon, jacob and Karl!