To be honest, I like the soundtrack of Victor Vran. So much that I would like to listen to it outside of the game. I see that it's available for purchase on Steam. I wonder if the developers are considering selling the soundtrack also on GOG? :)

The soundtrack is also available on amazon's mp3 store for $8.99, might also be on itunes (however I don't use itunes).
No idea if the soundtrack will be released as DLC for the GOG version of Victor Vran.

During Steams summer 2016 sale, I rebought Victor Vran just for the soundtrack.
VV was heavily discounted and even with the soundtrack DLC, it was cheaper than buying it off