Obviously fair share of problems, but there were some clever workarounds with "hyper triggers" to make triggers fire very often, instead of being recalculated every 2 (?) seconds... or stuff like counting minerals to do things (what to be honest was horrible, but worked).
Those custom maps grew as our computers grew (I cant imagine some of the custom maps working with 16mb of RAM, luckily I upgraded to I think 192) and spawned whole generes - MOBAs and Turret defense. There was even that "the unknown" map what is basically Among Us long before Among us.
Are there any games nowadays that allow such things and spawn so many custom maps?