GraviTron is a side-scrolling game in the style of Thrust and Lunar Lander. The objective is to navigate a spaceship over different planets, and destroy the reactors located there. The spaceship can rotate clockwise and counterclockwise as well as thrust forward, to avoid the pulling force of gravity. The spaceship can also fire lasers straight ahead and wrap itself in a protective shield which also deflects enemy fire. Points are awarded for the number of enemies destroyed, with higher scores given for using the shield deflection. Additionally, each planet has a number of spacemen walking the surface who can be rescued for extra points. In order to make the rescue, the player simply has to land carefully on a flat, even surface near the spacemen.

Also featured is a multiplayer deathmatch mode and a level editor for designing one's own planets.