Cheat Mode:
Pause gameplay then hold L + R and press Down, A, X, Black, B, A. The phrase 'Enter Cheat' will appear to confirm correct code entry. The following codes can now be enabled when you release L + R.

Unlock God Mode:
White, Black, Y, White, Left Trigger, Left Trigger. Your Health Meter will decrease but you won't die.

Unlock Unlimited Ammo:
Left Trigger, Y, B, Up, A, A.

Full Adrenaline Meter:
B, Y, Right, X, A, X.