NOBODY?

Wow, no wonder the support for this game BLOWS.

GOG version works fine for me. Never had the problem you have. Why are you looking for help for the Steam version here?

I don't have any problems whatsoever running the game (GOG version, standalone, without Steam or Galaxy or any other client), unless you count the fact that until now (one and a half scenarios), it is pretty disappointing.

Are you playing the GOG version or the Steam version?
If the GOG, why are you running it via Steam? Do you see the same behaviour without Steam?
If the Steam, why are you asking about it on the GOG forum rather than on the Steam forum?

This isn't where you come to contact support. This is where you post to see if someone else had the same problem and what they did to solve it thereby solving your problem quicker. But when there's no one here who had that same problem you would have to contact their support. Mail them at this support@creativeforge.pl and describe your issue properly. Give them your specs and attach your dxdiag to the mail as well.

We actually have people responding to every single email we receive at our support@creativeforge.pl (the one that Hunter 65536 already posted kindly).

Anyway, the issue you're describing is a new one to me. I'll try to remember to ask our support team tomorrow, maybe they've received other reports for the same issue already and will know how to fix that. It would also help if you posted both your specs and the actual framerate.

Edit: I asked. It seems to be a known issue but our support team does not have a solution yet. My best guess would be that it's actually caused by a too high frame rate and will go away if you turn on vsync, but no guarantees. I'm quite sure that it's a general problem with the Unity engine, will have to do some research on this matter.