800 Fathoms

800 Fathoms is an under-water themed side-scrolling shoot-em-up with gameplay similar to Konami's Scramble . You are a commander in control a submarine which can shoot horizontally, and deploy depth charges (diagonally fowards and down). With these armaments, you must defeat enemies from the mysterious marine empire. As you move about, your fuel will decrease. Fuel can be replenished by destroying fuel depots. Points are awarded for shooting enemy vehicles and other structures.

There are five stages of play. The first is to get past defensive barricades with walls and bombs. The second is to avoid boats dropping depth charges. The third is to survive missiles launched from the sea floor. The fourth stage contains torpedo launching bases, and the fifth requires you to slip through a field of deadly oscillations. After each stage, you must defeat an end-of-stage boss that shoots prodigious numbers of torpedos. After completing all five stages, the game loops at a higher difficulty level.