I have one problem that they stopped counting achievements? The situation is this:
Initially, I played 25 hours, everything was fine, then I did not play for about half a year, and now I started playing the game again. And now, for another 50 hours I played, not one achievement was counted, although I decently passed the game. Has anyone come across a similar one?

I have just begun playing this game within the last week, can confirm that achievements are not registering for me either. Latest GOG version, unmodified.

EDIT: I tend to close the Galaxy launcher after the game launches - that might be an issue. Do you have the launcher running in the background while playing?

EDIT 2: No difference with launcher open in background or not.

Can confirm this, three of my achievements should have been unlocked, but were not. Luckily I dont really care. I dont see any option to change difficulty levels, but others have discussed beating the game on different levels. ?

I can only speak for myself, not the other poster, but Im not sure how to check if the achievements will unlock and Im pretty sure they wont unlock retroactively? Ive already passed the nutcracker, dug the graves... So in other words, Im not sure which achievement Im approaching next. If I do unlock any, I can post on here. Great game by the way. Fantastic actually, better than I expected. As someone who has dabbled in writing, I appreciate the unique writing style.