Thanks for the speedy reply, but I have no idea how to do what you recommended.
What he means is where you put the game. If you use your own folder structure and it looks like this (I am exaggerating a bit of course)
C:\MyPersonalFolder\Games\RecreationalGames\Certainlynotporngames\Noreallythesearelegitgames\WithArcadeAndActionAndStuffLikeThat\F95\Downloads\MidnightSind0-3-0\MidnightSin
Then it becomes too long with all the internal structure the game has, since Windows has a max length for filenames including the whole path above. So if you just copied the main game folder to something shorter like
C:\MyPersonalFolder\Games\RecreationalGames\MidnightSin
it might work like it is.