Pause gameplay, hold Left Trigger and press Y, B, Y, B.
Get Mutant Mode
Pause gameplay, hold Left Trigger and press Y, B, X, X.
Get Squeaky Voices
Pause gameplay, hold Left Trigger and press Y, X, Y, Y.
Get Welsh Mode
Pause gameplay, hold Left Trigger and press Y, Y, Y, Y.
Enable Real Controls
Pause gameplay, hold Left Trigger and press Y, Y, Y, B.
Get Turbo Mode
Pause the gameplay, hold L and press Y, B, X, X.
Glitch: Missing Character
Enable the first person code. At the end of a game of Roller Ball, your character won't be there if you won!
Advanced Mutant Mode
Pause gameplay during a mini-game, hold left trigger and press YBXX. This gives you big heads. To get mutant mode two (giant characters) repeat code. To get mutant mode three (streched characters) repeat code. Repeat a fourth time to disable code.