If you need help to progress in the game then try entering this batch of codes. To enter the codes hold L1 and R1 during the game and then the code for the effect you want to enable. To disable the code just re-enter the code again.
Press Up, Down, Left, Right, Right, Left, Down, Up.
Unlock Infinite Weapons:
Triangle, Triangle, Down, Down.
Unlock Killer Weapons (Super Damage):
Press X, X, Up, Up.
Unlock Mega Guns:
Press X, Triangle, X, Triangle.
Trade Weapons for Health:
Press Triangle, X, Square, Circle.
Press Left, Left, Up, Down, Left, Right.
Added by: Sanzano Feb 11th 2008, ID#29147