At the main menu, select Extra, and then enter the following codes to unlock that corresponding cheat to that code.
Extreme Ragdoll: Press up,up,up,R2,R2,up (this code when activated will cause the enemy to fly off into the air when shooting the tank on their backs or by an explosion)
Hippy Blood: Press L2,right,circle,down, R1,select (this code will make all the enemies blood look like flowers)
Infinite Health: Press Left,right,up,down,L3,square ( this code will give you infinite health at all times)
Infinite Supplies: Press Select,R1,L1,select,R3,L1 (this code will give you infinite ammo, and others supplies you have)
Low Ragdoll: Press Square,square,circle,circle,up,down (this code is like the extreme ragdoll only your enemy does not fly off into the air as high or as far)