Tommy Gun

Level Codes:

02  442244
03  867377
04  835000
05  730098
End 655278

Cheats:

Press 'P' to pause the game, now press and hold down 
'G', 'U', and 'N'.  
The screen should flash indicating infinite everything, 
and pressing 'F1' through 'F5' will jump to the corresponding level 
and 'F6' will show you the end sequence.