> And since this game came out in 1983, it is safe to say it was selling on the number > one selling personal computer - the Commodore 64.
Manic Miner was converted to the commodore 64, but PacManicMinerMan was converted from the spectrum version.
In the 80's they were called computer games to differentiate them from board games. If you were more specific you said which computer.
AFAIK Personal Computer wasn't shortened to PC until IBM used it for their computer line. I don't recall it ever being used as a generic slang for all Personal Computers (in the UK a PC back then was a Police Constable).
No matter how popular you think using PC to mean all Personal Computers was, we're not in 1983 and today PC means something else.
You were at best ambiguous and at worst you were wrong, it's impossible for me to say which.