Press P to pause the game and type in these codes.

Code			Effect
booster			Full energy
luehmann		Invincible
just cut to the end	See ending video
go anywhere 		Level select
fruit			Go to Anything But Tangerines 	 
dublin			Go to Puppy Love	 
hoffman			Go to Flyin Kin	 
abrown 			Go to Cow Abduction 	
shiny shines 		Go to Inflated Head 
                                        

Note that these codes only work for the US version.      

Thanks to Revolution readers John Case III and Duderonamee!