There are cutscenes with a "Black Circle" on the sky.
Contacted Microids support and they told me my computer doesn't meet the minimum requirements.

CPU: i5-1235U (frequency 1.3GHz but 3.30 GHz are required (namely i5 6600))
Graphic: Intel UHD is not powerful enough
PS. for comparison purpose, below is the core/thread, base and turbo boost between mentioned CPUs
i5 6600: C/T 4/4, base 3.3GHz, boost 3.9GHz
i5-1235U: C/T 10/12, base 1.3GHz, boost 4.4GHz

Yeah I know my computer is not powerful enough and not expecting it run over 30fps, but expect nothing like a graphic issue as I attached.
In fact, it run something between 15 and 25 fps judging from my naked eyes. In the ending cutscene where the train crossing the bridge and the camera panning toward the sky it dropped to 4 fps (with GOG layer fps counter on).

Can anyone tell me what the black circle is? (I assume it is the sun)
With that information I can contact Intel and see what they can do about it.