Cheats:
Hold L1 + R1 and press Square, Circle, Triangle, X(2) during game play to display the code entry screen. You can then enable any of the following codes to activate the corresponding cheat function. Enabling a code will disable game saves.
Full health
Hold L1 + R1 and press Triangle, Square(2), Triangle, X, Circle during game play.
Full ammunition
Hold L1 + R1 and press Circle(2), Triangle, Square, X, Triangle during game play.