Type them in the map screen.
ix1 - all locations visible
ix2 - 10 skill points to every marine
ix3 - 500 equipment points for your stock
ix4 - skips to next mission
When playing the game you type in:
YOUARESTUPID you will be able to use the super laser.
BUGGEROFF giant jump pack
GENEJONEGINGLELHON You get a special character.