Pac-Tac is one of the earliest Pac Man clones. Like several other games published in the 1981-early 1982 era, it used the Semigraphics-24 graphics mode in order to get 9 colors on the screen at once, even thought it had a really weird resolution (64x192). It had really grating sound effects when you died, and had a more complicated maze (with more power pills) than the original arcade. It was later redone in PMODE 4 graphics mode (256x192x4 with artifacted colors) as Pac-Tac II (This also allowed it to be run on a Coco 3, as the Coco 3 does NOT support the Semigraphics-24 mode). Also, a Tom Mix Pacman clone called Snak Pak seemed to share the same sound routines as this original.
An interesting bit of trivia, from the 6th issue of Computer Gaming World magazine (Sep/Oct 1982), from Computerware themselves: they had sold 5,000 copies of Pac-Tac between it's release in September of 1981 until the end of June 1982.
Title: Pac-Tac
Author: B.J. Chambless
Publisher: Computerware
Released: September 1981
Requires: Color Computer 1 or 2 ONLY, 16K RAM, tape or disk, joystick.