Go to the main menu then use the following codes to unlock everything in the game (all Costumes, all Cerebro Files, Level Select and pause menu cheats):

B, X, B, Y, Y, Y, L, L, Z

B, X, B, Y, Y, Y, R, R, Z

B, X, B, Y, B, X, L, R, Z

B, B, X, X, Y, Y, X, X, L, L, R, R, Z