Earthworm Jim

You can type these codes during the game:

HATMAN                - Jim changes into hatman
ITSAWONDERFUL         - Extra life
ONANDONANDON          - Extra continue
SLAUGHTERHOUSE        - First 5 levels are available
POPQUIZHOTSHOT        - 1000 bullets
BLOATED               - Jim has an afro
SWEATY                - Big lips Jim
THREEMILEISLAND       - 100% energy
GETTHECHEESETOSICKBAY - All levels

You will hear Jim call you a 'Cheater' 
when you type in the code correctly