Hidden Options 
 The password for the hidden option vs. Computer in the game is:
 DOAKSIM 
 
 Other Passwords 
 Type the following codes in the "Password Entry" section: 
 
 KIKMAHP 
 DKRORCR 
 STKZJGH 
 
 They activate: 
 
 1) Free Play (Infinte Continue) 
 2) Allow access to all boss in Boss Mode 
 3) Allow access to all levels in Drill Mode 
 4) Allow access to all CPU characters (Citizens, Harry, etc...)