I have the game in Steam but at some point whenever I launched it it just made my two monitrs switch off as if they were disconnected and the only thing I could do is restart the PC. I bought it again here hoping it will be different. Launched the game and it started OK but in a windowed mode. I made it full screen using ALT+ENTER and this brought me back to my 2 displays switching off. Unfortunately there is no config in GOG Galaxy allowing me to start the game in windowed mode so I am pretty much stuck. Re-installing the game didn't work in Steam so I suppose it wouldn't work in Galaxy either. Any ideas?

there's the options screen which lets you check a box to make the game in full screen, unless you actually meant the game doesn't work while in full screen?

uncheck box then check again? or uncheck box then restart the game?

That's it.

The only thing I can think of is that you probably can't have both the steam & GOG version on the hard drive installed at the same time?

I'm not sure though. Maybe you should write to support if you haven't done so.

Done. They propose a refund, that I didn't asked at first. Maybe GOG was aware they were selling a no working game.
So everybody should ask a refund of this game to GOG.

well, maybe just to people who the game doesn't work for. I bought the game and it worked for me. In fact I finished it a short time ago.

Good luck.