Based on 1987 Sega coin-op.
U.S. Release (front) [Source: Moby Games]
U.S. Release (back) [Source: Moby Games]
UK Advert [2] [Source: Atari Mania]
Pause the game and type “LARSXVIII” for infinite credits or hold the LEFT MOUSE BUTTON, then type “LARSXVIII” for invincibility. Press ‘Q’ while game is paused, for music menu.
On the helicopter boss pause the game and type “HELICOPTERTOOTOUGHFORME”. Then die and you will then go to level 3 (if you have another life left).