Doc from the amazing gog support showed me some tips and it kinda worked for me, at least so far:
Please follow these steps:
1) Please add GOG GALAXY folders:
C:\Program Files (x86)\GOG GALAXY
to all of your security (antivirus, antyspyware, firewall) software exceptions list. If the game is installed outside of GOG GALAXY folder, then please add game's installation folder to security software exceptions list as well. Once above is done, please select the game in GOG GALAXY, click on Customize -> Manage Installation -> Verify/Repair. https://imgur.com/mPXqg0n
2) Reinstall the June 2010 DirectX runtime package. You can find the archive file containing the 2010 package installation files here: https://files.gog.com/support/Directx_Jun2010_redist.exe
You will have to extract the files into some folder, then open that folder and launch the DXSETUP.exe file in order to proceed with the installation.
Please have in mind that this will only add DirectX 9.0c to available pool of DirectX libraries, and it will not overwrite your other versions. Some games are not able to utilize newer DirectX libraries, and they require DirectX 9.0c.
3) Please update your graphics device drivers: https://support.amd.com/download
(my card's a radeon one)
check my attachments for settings et al and here, too https://imgur.com/BnMeW6Z