Killer Tank 
 
Press "T", then enter the following:

Code        Result
------------------                       
AECHEATS  - Cheats enabled
AEDQD     - God Mode
AECLEV XY - Go to level, where X is the campaign number 
            (1 or 2) and Y is the mission number (4 to 7)
AEFA      - All weapons, ammo, power-ups