Game Genie Codes 
     110-118-110   No unarmed enemies
                   Removes enemies that don't use guns

Passwords 
     Here's some passwords to help you out. 

     Level    Password
     2        GRZNNPCRDB
     3        DVZNDPBTNG
     4        GVZNDPBTNG
     5        PCVYGRBTDK
     6        RCVYGRSTDR
     7        VSVYTRSQDG
     8        RSQPTNSQNW