Alexim: Yeah, and I don't want to jump to conclusions, but the game Tempest doesn't really feel DRM-free to me, because with Galaxy down I can't start it in any way.
Geralt_of_Rivia: I find that hard to believe. Let me check...
[Installing latest version of Tempest with all DLCs]
Runs just fine without even having Galaxy installed.
Oh, wait, I have a hunch...
[checked my hunch]
Yeah, I was right. The devs are using an ancient version of the Galaxy DLL. As a result you must not use a firewall to block localhost (127.0.0.1) or the game will crash on startup.
It's a well known bug of old Galaxy.dll versions. Details here:
https://www.gog.com/forum/general/crashes_in_games_with_galaxydll_or_galaxy64dll/post8 Thank you very much, I was confident that there was some explanation, but I didn't know about this umpteenth problem with Galaxy DLL. I see that GOG cares about applying Murphy's Law as much as possible.