I am unable to unlock achievements although I have tried playing on the lastest version (1.9) and prior ones (version Stasis Mode update, Version 1.7 Hotfix, version 1.4(g) and version 1.4(gog-3). Can someone give advice regarding the issue? Thank you:).

Ive also faced the same problem and have been in contact with Team17 about it.

Same issue of achievements not unlocking at all and Ive sent them my save data for analysis. Will update when I get a response.