I've tried this game a few years ago and it was nothing. Today I've decided to recheck it, saw the same pathetic mention on the gog store page that the game doesn't work on Win 10, but when I launch it, it played without and issue. What happened? Win 10 got better compatibility with old junk? Or it is because I'm on Intel GFX currently, not the Nvidia.

My guess is that it has always worked.
Likely the thing is GOG offers limited or no support for Windows 10 users.

Gradually GOG has been updating their compatibility for old games on Win10. Unfortunately (and it's a stupid decision on GOG's part) they seem to forget to update the games pages concerning the new compatibility.

I'll give the example of Final Liberation: Warhammer Epic 40K : in early 2020 the game wouldn't work on Win10. Yet, sometime in mid-year the game began working flawlessly on W10 because of some fix GOG did. Yet they forgot to announce that the game now works for the new OS :P