Last time I coul launch the game successfully was a year ago.

Now I have a 0xc000007b error (when trying to launch the game from the folder) and nothing at all when trying to launch it from Galaxy.

My runtime libraries are up-to-date (I'm running Windows 10 Pro 64-bit)

I tried reinstalling the game from Galaxy (doesn't solve the launching problem) as well as dowloading an .exe file from my GOG.com account in order to install the game "outside" of Galaxy, but it didn't help either.

Also I noticed that the installer from Galaxy only shows 62 MB to be downloaded/installed, and not the 277 MB the game is supposed to weigh according to the installation settings window... Is this normal?

You can try rename/relocate the savegame folder, it should be somewhere in the documents folder.
If it works the savefile has become corrupted.

Maybe anit-virus is blocking execution?

I tried starting the game - and even reinstalling it again - with all anti-virus deactivated (the windows one as well) but I still have the same 0xc000007b error. I could "repair" the game and install a 117 MB update though, but it didn't change anyting.

Do you use Galaxy?
If so try running the executable directly from the gamefolder.

edit:
Nevermind, I see you already tried that.

I'm running out of ideas, you could try the standalone installer or contact support to help with your problem.

Already did... doesn't work either.

Thanks for your help anyway. At this point I'm more curious than anything, because it's the first time I meet this particular problem with a game.

You can replace the dll's, someone with same error said this worked.

https://www.youtube.com/watch?v=gLZrB_pRfzE

Or try installing this

http://www.microsoft.com/en-us/download/details.aspx?id=8109