You already unlocked some achievments in the game but don`t got them on Steam? Maybe this little guide will fix it for you until a official bug fix is out.
How to Unlock Steam Achievments!
There is a bug with the steam achievments not unlocking but if you look at your achievments in game you can see the progress or if you unlocked them or not.
I was just playing the game and somehow lost my connection to the game and it asked me to play offline and I just pressed yes. After my connection was back again I reconnected to “online” and I unlocked the same steam achievments like I see them in the game. So I wanted to check that out and played until I got another achievment but again it did not unlocked on steam.
So I tried to deactivate my “wlan or lan” connection in the windows settings and just tabbed out of the game and again the game asked me to go offline so I did this and go back to windows settings and enabled my connection again and my next missing steam achievment popped up.
All in all I can say to unlock steam achievments you need to be in the game (online) than tab out of the game and go to your windows settings to deactivate your wlan or lan connection go back to the game and than the game asks you to change to the offline mode just say yes tab out again go to your windows settings and activate your wlan or lan connection again go back to the game and change the game back to “online mode”. Now you should get your missing steam achievments.
It looks like you have to do this everytime you want to unlock your ingame achievments on steam.
I don`t know if everyone has this problem maybe because I did not linked my account or whatever but maybe it will fix it for you too.