Lunar Battle © 1982 Atari.

Prototype version of "Gravitar". Here is the list of differences with the final version:
* There are ONLY 2 Solar Systems (three in Gravitar).
* Different Planet, Bunker and Fuel Cell icons.
* Different bunkers' and planets' shapes.
* No planet animations.
* Stronger and more intense Gravity (Game-play is much harder).
* Some sounds are different during the game.
* There is an additional 'Low on Fuel' warning if the fuel level drops below 2000 fuel units that is not present in Gravitar.
* Rammer ships are present in the south planet of the second solar system - Not in Gravitar.