To receive all nine weapons, full life and proximity mines, 
press and hold the letters W, A, and X all at the same time. 
Note: Your score is set back to zero every time you use this 
code. You can also gain access to individual cheats by 
typing C7 LEVEL1 DIAGNOSTIC at the DOS prompt when you begin 
the game. Then, during play, try these key combinations: 

          BackspaceG: Toggles God mode on or off. 
          BackspaceW: Warps between levels. 
          BackspaceN: Lets you walk through walls. 
          BackspaceR: Puts a skull image in front of your   
                      character. 
          BackspaceI: Increases your score.