At the character selection screen, choose Load and enter the following:

Code			Unlocks



FATHEAD			Full Cheats  

ENCHILADA!		""     ""

BRAINSALAD		Brian The Brain and Space World

CODY 			Invincibility
FANPLASTIC		'Plastic' graphics

GUNSMOKE! 		Ranged weapons

MELEEDEATH 		Melee weapons

MULTIPLEX!		All FMV

PENCILS			Pen and ink graphics

TWRECKSPAD		T. Wrecks and Jungle World

UNIQUEWPNS		Personal weapons

WHACKLAND       Whack ANgus and Desert Level

EARLSPLACE      Count Earl and Transylvania World

Big Head mode:
During play, press L + R + Up.

Thanks to Revolution readers Shadow, tommy clarke, Whack Angus, Jeff Perrin, Adrian Martinez and Martiniman!