Invincibility:
Enter LRGARMS as a code.

Level select:
Enter PASSKEY as a code.

Level skip:
Enter QUITER as a code.

All combos:
Enter NINJA as a code.

All weapons:
Enter STRAPPED as a code.

Maximum ammunition:
Enter MRJUAREZ as a code.

Maximum damage:
Enter SPINACH as a code.

Extra health:
Enter BUTTERUP as a code.

Play as Clown:
Enter SCARYCLOWN as a code.

Play as Convict:
Enter JAILBREAK as a code.

Play as GI:
Enter GNRLINFANTRY as a code.

Play as Lizard:
Enter HISSSS as a code.

Play as Moseley:
Enter BIGLIPS as a code.

Play as Nara:
Enter WEIGHTGAIN as a code.

Play as Nikki:
Enter HAIRLOSS as a code.

Play as Robot:
Enter MRROBOTO as a code.

Play as Superhero:
Enter SUPERJOHN as a code.

Play as Zombie:
Enter IAMSODEAD as a code.

Free aim:
Enter FPSSTYLE as a code.

Pain arenas:
Enter MAXIMUMHURT as a code.

Armor:
Enter STEELUP as a code.

Baseball bat:
Enter SLUGGER as a code.

Rag doll:
Enter CLUMSY as a code.

Slow motion button:
Enter SLIZOMIZO as a code.

Bouncy men:
Enter BOUNZMEN as a code.

Cluttered locations:
Enter CLUTZ as a code.

Dramatic finish:
Enter STYLIN as a code.

Ending sequence:
Enter WIMP as a code.

Concept art:
Enter SKETCHPAD as a code.

All FMV sequences:
Enter DIRECTOR as a code.

Do not select:
Enter DONOTSEL as a code.