Thanks for your explanations. GOG Galaxy is somehow problematic to run under Wine [1]. No (local) achievements in not a big problem, however, in hindsight, I could buy a Humble (widget)/Ichi version instead.
[1] - I remember that Linux is not supported, however, probably not all (Windows) people also use GOG Galaxy, so there could be a choice for a standalone version to have only local achievements (just an idea).