After briefing for the second mission of Scaevola completes (the one about reclaiming Destroyer samples), game freezes and you can't advance or cancel. Game is still semi-responsive, as e. g. you can press space and see noosphere, but you can't proceed to mission.

Might be related to https://www.gog.com/forum/warhammer_40000_mechanicus/cant_get_working_the_sound_in_this_game issue that I'm experiencing.

I have figured out a solution for my case. Apparently Unity engine is not really compatible with most sound-enhancing software, such as Asus Sonic Studio which came prebundled with my laptop. After I uninstalled and restarted my computer, sound was fixed and freeze problem went away.