X2: Wolverine's Revenge cheats and cheat codes for Gamecube

Unlock cheats option 
Hit B, B, X, X, Y, Y, X, X, L, L, R, R, Z at the main menu.
Pause the game play to get access to the unlocked "Cheats" option.

Unlock Cerebro Files and movies:
Hit B, X, B, Y, Y, Y, R, R, Z at the main menu.

Unlock all outfits:
Hit B, X, B, Y, Y, Y, L, L, Z at the main menu.

Stage select and all challenges 
Hit B, X, B, Y, B, X, L, R, Z at the main menu.
Note: Collect all the tags you need before enable this cheat code, 
because you cannot advance to a higher level after used this code.
After you enabled this cheat, all your saved game file marked with X.

Blooper movie sequences
Finish the Gold, Silver and Bronze challenges, after go back to the title screen 
then choose the "Bonus" tab. Go to "Gallery" and pick "Play Movies." 
Jump to the bottom of the screen and check the last 3 movies.