Hello. Could someone explain to me why GOG Galaxy 2.0 did not charge me 100% of my achieved achievements, even though I received a notification on my profile? Despite all the achievements unlocked, GOG Galaxy 2.0 shows only 99% and 98% on the profile (photos attached), so I do not have the first place in the ranking. Did I do something wrong and is there any way to fix it?

Hey dude! I would imagine it's a bug with galaxy and/or profile itself. Second guess would be that the game used to have more achievements, but one or more got delisted. However the old total is still applied. Something like this happened with Homeworld remastered collection, but gog only hid the broken achievement and it's description, but you can still see its icon - which is not the case with Fallout NV.

So dunno, I guess it's just the former - a bug with galaxy itself. Seeing as I have stuck/broken steam integration for months now, it wouldn't surprise me at all. Still it sucks... hope these things get fixed.

I have the same problem with The Uncertain: Last Quite Day. It shows that I have done the 97% of the achievements although I have unlocked everyone of them.

It's a well known problem (or at least it should be by now xD). Happens to different games but manifests the same in %.
Hopefully, GOG.com stuff will have it sorted soon.

I have the same problem with Metro Exodus. I have all achievements but Galaxy shows 98%.
This is quite annoying because I have some other games where I was close to getting all achievements but I had to put them on hold because I don't want to have stats broken for them as well. Idk if they are working on the fix. The support is silent. I wrote about this issue more than a month ago but still haven't received any reply.

FYI: i have had the same issue with other game(s) as well & opened a ticket (some time ago) - ticket status is still "open", but: those games have now the "100%" progress on (web) profile. Check it, may be they solved it on their system, so that your problem has been also fixed.

What i can add for one game, is: Cyberpunk 2077 have no percentage progress on web profile whatsoever. :-)
Maybe they add this later on.