Unlock Cheat Mode:
To unlock Cheat Mode, finish all objectives in the single player missions. Once Cheat Mode is unlocked, the cheats will be made available.
Fat Players:
Hold BACK and press B, B, Y, X, X, A.
Team God Mode:
Unlock Cheat Mode, then press and hold BACK, and press B, A, Y, Y, B, A, X, X, X. You will not be able to complete the game with this cheat enabled.
Big Heads:
Hold BACK and press A, X, B, Y, A during game play. A message will confirm correct code entry.
Bunker Brush Glitch:
In multi-player map number 8 (the POW camp) head into one of the bunkers you need to duck to go into. Occasionally, if you stand up you will be able to see and fire though the bunker