First Step
Before you enter any cheats, you must enter the following code for them to work. Pause the game. Then, for the PlayStation 2, hold "L1" and "R1" and press "Circle" twice, "Left," "Triangle," "Circle" and "X." Release "L1" and "R1." For the GameCube, hold "L" and "R" and then press "Up," "Y" twice, "B," "Up" and "A." Release "L" and "R." For the Xbox, hold "L" and "R" and press "Down," "A," "X," "Black," "B" and "A." Release "L" and "R."
Infinite Ammo
You'll need plenty of ammo to keep yourself alive in this game. Picking up ammo is the usual method to keep yourself replenished, but this cheat will keep you stocked up for good. For the PlayStation 2, press "L2," "L1," "Square," "L2," "L1" and "R1." For the GameCube, press "Z," "R," "Up," "X," "B" and "A". For the Xbox, press "L," "Y," "B," "Up" and "A" twice.
Kill the Nemesis
Several levels in the game feature a nemesis from the enemy side that you must hunt down and kill. Normally, you have to find him to dispose of him, but with this code, he will simply drop dead. For the PlayStation 2, press "Down," "L2," "L1," "Up" and "Square." For the GameCube, press "L," "Y," "L," "Z," "L" and "Z." For the Xbox, press "Right," "Left," "R," "L," "X" and "Y."
Get Rid of Shell Shock
In the heat of battle, shell shock can overcome you. Your vision will weaken, your perception will be off and fatigue will take over. This code stops any sign of shell shock. For the PlayStation 2, press "L2," "R1," "L2," "L1" and "Triangle" twice. For the GameCube, press "Z," "R," "X" and "Y" twice. For the Xbox, press "X," "Y," "A," "B," "L" and "X."
Suicide
It may not seem like a cheat, but if you're looking for a quick exit from the level, this code will instantly kill your character. For the PlayStation 2, press "X," "Triangle," "Circle," "Right," "Triangle" and "Circle." For the GameCube, press "L," "Z," "R," "Up," "A" and "Z." For the Xbox, press "B," "R," "White," "Y," "L" and "White."