Press ENTER to display the console window, then activate the following cheats by entering the corresponding codes and pressing ENTER:

CHEAT FUNCTION - CHEAT CODE
God mode - SheepInTheTrees or FreeWestMemphis3
1000 experience points - SpotTheBraincell
1000 prestige-points - MoneySong
Instant kill - TheSpanishInquisition or Inferno
Unlimited cargo for repair trucks - BicycleRepairMan
Invincibility - SelfDefenceAgainstFreshFruit
100 more outside support - MrHilter
Successfully complete current level - DirtyHungarianPhrasebook
Instant loss - TheFunniestJokeInTheWorld