Cheat mode
Pause the game, then hold L and press Start, A, White, Up, Right, Down, A, Y, B, A, B, Y to unlock all cheats, levels, FMV sequences, McSqueeb, Officer Dick, and Spider-Man. If you entered the code correctly, the pause screen will shake. -From: MaximumGQ @ aol.com

All levels
Pause the game, then hold L and press Down, Up, Left(2), B, A, B, Y to unlock all levels. If you entered the code correctly, the pause screen will shake.

Hidden cut level
Pause the game, then hold L and press Up, Down, Up, Left, Up, Right, Left, Down, Up, Right, Left, Right(3), Up, Down, X, Y, Up, Left to unlock the hidden level that was cut from the game. If you entered the code correctly, the pause screen will shake.

Treyarch decks
Pause the game, then hold L and press White, B, Up, A, Right, Down, Start. If you entered the code correctly, the screen will shake.

No blood
Pause the game, then hold L and press Start, Black, A, B, Start. If you entered the code correctly, the screen will shake.