Enter the following code at the "Cheats" sub-menu, which is found at the main screen by going to "Extras", then "Cheats":
This will unlock all in-game cheats. It has to be "activated" by putting a checkmark next to it. You can also access this menu during game play by pressing [Esc], then going to "Cheats". The cheat options are as follows:
- Super Health: Health quickly regenerates over time.
- Infinite Ammunition: Self-explanatory.
- Infinite Grenades: Self-explanatory.
- Reign Of Fire: All weapons make the target burst in flames after they are shot.
- Explosive Personality: When pressing [Use] (default E) on someone, they gib.
- Walking Dead: Makes everyone resemble zombies.
- Gibby Ammo: Shoot one round and the victim gibs.
- Gibby Explosions: Explosions make everything in its path gib.
- Rapid Rails: RailGun shoots very fast.
- Extra Chunky: Every time you shoot an enemy, you get a gib part (only visually with no hole).
- Wacky Deaths: When shot in front, some enemies you kill die as if hit hard in the stomach; when shot in back they look like they tripped on something.