I have a Macbook Air 2014 with macOS High Sierra.

These two game do not launch at all.

Hotline Maimi gives me an error message when i launch.
System Shock 2 does not give any message and show up at all.

How do i file a complaint on GOG to the devs?

I'm running into the same problem with System Shock 2. Are there known issues with running SS2 on macOS High Sierra?

Same here, SS2 doesn't launch. I only have Galaxy Client running. Doesn't matter if I try to launch the game from the Client or Finder, just never launches, no messages, no "not responding" or anything.

Edit: Running on Mac Mini 2017, i7, 8GB RAM - MacOS 10.13.2