Hey, I hope you've found the solution, but in case you haven't I followed a Steam answer and it worked for me! Credit to LeCrinjus:
".. All you need to do is to download NW.JS for your Linux distro (version 0.38.2 seems to work best), copy all the files inside the zipped archive and paste them into the game's path (/<steam path>/steamapps/common/Fear & Hunger).
After that you can directly run the "nw" executable in there and it'll open up the game. Just make sure the "package.json" file and "www" folder are in the same path as the "nw" executable so it can load the game files."
Original discussion.
I used the latest stable NW.JS and when it prompted confirmation for merge/replace, I answered yes to all files. Enjoy :D