icon58 Thanks for the log, but probably the Player-prev.log would contain the relevant information
However, if it's the same issue as noci is having, then it indicates that you are launching the .exe directly, i.e. not through Steam? Is that correct?
The game previously shipped a steam_appid.txt file, but Valve doesn't want that such a file is shipped (so we've removed it for the store page update). However, without this file, Steam is unable to determine the AppID of the game, so it quits the game and launches it again through Steam. This is intended behaviour of Steam (but IMHO it's no good behaviour).
You can fix this issue by downloading the attached file and put it into your game directory (where the .exe is located), that should do the trick 
We'll also consider to ship this file again in future updates (or maybe implement a different solution).