Do achievements even works for this game? I'm few hour in and couldn't unlock any of them... I know there are some like "become adult" which means finishing prologue or sleeping at camp, I did both, but didn't unlock anything

It's possible an update broke achievement support, you'd have to check this by using Galaxy to roll back to a previous version and try fulfilling the achievement condition again. I know achievements were working in at least an earlier version since I unlocked some, but the computer I'm currently on is a potato and I can't run this game right now to test it.

Thanks for trying help, its quite possible its fault of last update, because some people unlocked achievements, when you check % of players who achieved something in GOG Galaxy. But these numbers are way smaller than Steam, according to them only 40% of players finished short prologue.
Anyway, how do I roll back to previous version? Is it possible if i bought it after latest update and didn't have installed previous versions? The only option I see in configure->auto-update is 2.11.

Now that you mention it, it looks like the ability to roll back is missing for many games with old versions. I don't know if it's a bug or if GOG was cleaning house. =\ Sorry, I'll see if support knows what happened.