Master Codes:

To start one of these codes simply type the letter T, then the code and then type ENTER

Cheat Codes:

mcgee - Sets yourself on fire
onering - Makes you invisible
nocapinmyass - Makes you invulnerable
eva galli - Switches off clipping
goonies - Shows you all of the map
idaho - Gives you all the weapons and ammo for them
buns - Gives all weapons, ammo and dual weapons
keymaster - Gives you all the keys
satchel - Gives you all the game items
griswold - Gives you maximum armour