I've noticed a recent trend of games here having issues that are solved by uninstalling and reinstalling the game. War for the Overworld, Planet Nomads, Star Vikings Forever, and now Sublevel Zero are all examples of this. In each case I know of, some issue has been caused by updating an existing install, and the only fix is to uninstall the game and do a fresh install of it. Does anyone at GOG know why this is happening?

Very simple,the games are that excited to be played that they skip a file or two instead of slow and steady wins the race.

This only happened to me with mount and blade warbard where the patch didn't work but unistalling the game and installing the full new installer did work.

Looks like buying hugely overpriced, shovelware on day 1 release causes issue, who would have thought...
The real trend here is that anything released nowadays in this modern and forward thinking store is 99% garbage, released early or half done, and this is why we need a shovelware patcher to keep the game (sorry, use the term in the loosest possible manner here) up to date, or to download the various parts (also know as DLC) of the original product.

This has now been an issue with Little Nightmares as well. Going to Chapter Selection after updating the game for the first DLC caused a crash. Uninstalling and reinstalling everything has fixed the issue.

GOG, can you please do something about this?