GOG version of game goes to black at start

So I start install the GOG game on my Mac Pro, I get the start screen, the first time I do this I make it a few minutes into the game, created avatar and whatnot, I save and shut down, later retart the game and every time it just goes to black. I hear the ambient audio, and see the cursor, but no image, nothing. After I trashed the game (and all the pref. files etc. I could find) and reinstall (twice), now I hear the opening narrative, but still no picture, nothing happens clicking around.

Any thoughts?