edisoncarter has found a decent cheat, probably more useful for newbies I guess, since it gives you infinite health. There's also a cheat which we don't know the affect of, so please inform us if you find out.

Infinite Health:

Makes you mostly bulletproof, and fire, punches and melee attacks don't hurt you anymore. You can still be hurt by explosions, falling, getting run over, and drowning.

Unknown Cheat

It is not currently known what this cheat actually does, please inform us if you find out

For all the cheats on one page click here.