Color Invaders was one of the first commercial clones of Space Invaders, along with the Spectral Associates version. It's main claim to fame (other than how early it was released for a 3rd party game) is that it cloned the Atari VCS (later called Atari 2600) version of the game, and not the arcade game, as one can tell by the look of the invaders... they are almost identical. I believe that the same author who did the original Pac-Tac did this game; the sound routines for blowing up aliens and eating the ghosts in Pac-Tac are the same.
It should be noted that a revised version with a copyright of 1982 was released that supported 2 players (taking turns). The original 1981 release had no option for 2 players.
Title: Color Invaders
Author: ???
Publisher: Computerware
Released: January 21, 1981
Requires: Color Computer 1,2,3, 16K RAM, tape or disk, joystick.