Space War was, I believe, the last game that Greg Zumwalt did for American Small Business Computers. After this, he started writing games for Tandy/Radio Shack.
It is a clone of the vector arcade game of the same name, released in 1977 by Cinematronic. That itself was inspired by the original PDP version from 1962, one of the first video games ever made. It is a two player game, pitting two spaceships against each other, who can damage each other’s ship (which causes a loss of your ship’s mobility), or outright destroy it. Like the original arcade version, it has a time limit (that you can extend… thankfully, without spending quarters like the arcade original).
Title: Space War
Author: Greg Zumwalt
Publisher: American Small Business Computers
Released: 1982
Requires: Color Computer 1/2/3, 16K RAM, joysticks.