Pause the game and type "A FINE KETTLE OF FISH". This gives you infinite lives and use of the following keys:
'F1'--STAGE 1.1 | 'F4'--STAGE 2.1'| F7'--STAGE 3.1
'F2'--STAGE 1.2 | 'F5'--STAGE 2.2'| F8'--STAGE 3.2
'F3'--TORTURE 1 | 'F6'--TORTURE 2'| F9'--TORTURE 3
'F10'--Skips to next level. | 'C'--Shuts cheat off.