Aquatron

Aquatron is a side-scrolling arcade shooter set on a planet completely covered by water. Players control a spaceship that can turn and travel both above and below the surface while fighting increasingly numerous enemies.

Ammo and shields are limited, but parachutes dropped by the home-base zeppelin can replenish them. Protecting the zeppelin is essential, since its destruction can leave the player without resupply until another base appears. Enemy-dropped parachutes become submarines when they reach the water.

With no defined ending, Aquatron focuses on achieving a high score. It was developed by Justin Gray and published by Sierra On-Line, Inc. for Apple II and Atari 8-bit.