PCGW recommends Zeckenseck's Glide Wrapper. Using this, I had CTD as soon as I set assignGModeName to Glide, with or without renaming glide2x.dll in the game dir. Using standard nglide it worked, as recommended here: https://www.gog.com/forum/kings_quest_series/kq8_wont_launch/post19
Gog version, win 10 pro Not sure if I should update the article but at least that way somebody might see it