The following codes should be entered as passwords on the title screen.
NOBRAKES Full engine power.
HARDGAME Makes the game harder.
DNUMUAHCS Ten times more energy, but only one life.
DIEALIENDIE All weapons on full power.
JJRULES Thirty-five lives, all weapons on full power.
WARHEAD Makes missiles detonate when they hit a target.
ELITEMASTER Weapons are ten times more powerful.
PETSKUMODE Enables reverse gear.
Thanks to Revolution readers fahad!