Go into the options and select "Cheats". Enter one of the following codes to activate the corresponding cheat function.

Effect	Code
Zombie skin	I FEEL LIKE SHIT
Pirate skin	KAIZOKU
Knight skin	I AM SHINY
Zombie motocross bike	RESURRECTED
Pirate motocross bike	I NEED SOME RUM
Knight motocross bike	GIVE ME A PONY
(Crazy) Monkey skin	BANANA LOVE
All skins, bikes, tracks	COW*CRAZY
God mode	KING CHRISTIAN