Enter the following passwords at the 
     Password screen:

     Invincibility: I.AM.IMORTAL 
     Unlimited ammo: LOADSOFSTUFF 
     Weird music: JOURNEYS.END 
     Level select: RABBITBADGER 
     Final level: ENDGAMELEVEL 
     Six bonus tracks: BONUS.LEVELS 
     All weapons: ALL.TOOLEDUP