You could actually contact GOG support as they do actually support the games. They may or may not be able to help you determine the cause of the problem but they'll certainly try - unlike pretty much every other game distributor online. They've helped me sort out many problems with games including:
- Blitzkrieg graphics problems
- The Nations, Alien Nations, Robin Hood blurry graphics (disable morphological filtering in ATI control panel)
- numerous other odd quirks, none of which are problems created by or caused by GOG whatsoever, and none of which they have any obligation to do anything about - but they do anyway.
Think about it, before online gaming where did people buy games? At Walmart, EB Games, Zellers, Target, other game retail stores. If those people had graphics problems with their games did they go apeshit angry at Walmart about it?
No, of course not. Why? Because Walmart didn't hire the programmers to write the game. Walmart just sells the games and if you have a problem with the game then contact the video game publisher or your video driver manufacturer - the two prime culprits of any video game problem other than problems specific to your own computer (ie: viruses, broken hardware, etc.)
How is this even a GOG problem at all? It isn't. But GOG's awesome support nonetheless supports the games to the best of their ability anyway even though they didn't write them in the first place. Something you wont get from any other video game retailer.
So stop shopping at GOG if you wish, but good luck getting any support from Steam, Origin, Uplay, or any other retailer for your games. It's always fun to have someone to blame whether they're responsible or not though isn't it.