Hi there. For some reason the achievements in Prodeus stopped popping up. I have unlocked some of them and they show up in my GOG profile. However, now the achievements have stopped unlocking. Curiously, the In-game achievement counter still works and I have for example unlocked the achievement for beating a level without taking damage.

I have already verified the game files and de-/reinstalled the game. I also stared a new campaign on the highest setting to make sure that it only the save file that is maybe broken but no, the achievements are still not unlockling in my GOG profile.

Any help would be appreciated

Okay for everyone who will have the same problem in the future, I found a solution even though it is a bit unorthodox .
When you go to the Appdata folder and then in the LocalLow folder you find the BoundingBox folder. In there in the settings folder you have the "NUMBER"_Achievements folder. In this folder, for some unknown reason some achievements were already unlocked. I set the flag to "False" and then I replayed some levels to unlock the achievements. Till now I haven't encountered any problems.

But try this under your own discretion.