something about polybius
secret government psychological experiments (having a root in real activities)
other fear based themes: data-mining, addiction, broad physical side-effects, the object being gone but having some fragment of documentation (the original post claimed to have a ROM image of the game),
the eerie (a thing that shouldn’t be there)
viral/anecdotal spread is the joke in of itself (polybius is known for asserting that historians shouldn’t be reporting unverified information)
seems to have started in 2000 (is about a “1981” game though)
appearance in gaming magazines in 2003 (via the owner of the site where it was first mentioned, leading some folks to say it was a “hoax” to drive traffic), which led to the sort of collective “firsthand” additions to the narrative/lore that you see with creepypastas, as well as the creation of some games based on the legend