1st Person View:
Pause, then type VIRTUAL1

1st person view without seeing your weapon(s):
Pause, then type VIRTUAL2

Secret moves code:
Pause, then type LIFEISUNFAIR. Now press CTRL+(1-6) and your character will do a move.

Play as Earthworm Jim:
At Player Select screen type GIMMEJIM

Ehsan Ghebraie, Ray Drake and Marie Kreegier