The advert mentions Atari, Com 64 and Vic 20. But the Commodore 64 version is nowere to be seen. The screenshot shown seems to be a mockup with a hi-res font compared to the Vic 20 edition, which could well be based on what the C64 version looked like.
It is plausible that all versions were developed by Don McGlauflin, so hopefully that is a lead to follow.
More on this one soon we hope.
Contributions: Peter Weighill