Didn't know where to post this so i decided to put it here. Maybe someone would be interested to know.
I asked the dev of the games
Silence of the Sleep,
and upcoming [url=http://www.gog.com/wishlist/games/the_human_gallery]The Human Gallery about releasing his games DRM-free and reaching out to GOG and this was his reply:
"Actually both of my games are DRM-free. Though you will need Steam to download them, other than that there are no copy protection of any kind.
As for GOG I've been thinking about that, but to be honest sales figures aren't too good and I wouldn't expect to sell too many copies over GOG. It would only add more questions with taxes and accounting, so at the moment I don't feel it's worth it. But if my games stars selling a bit better (mainly thinking of my upcoming project The Human Gallery) I will most definitely contact GOG! :)
Thanks for showing interest!"
Silence of the Sleep has 180 reviews on Steam, 82% positive, DISTRAINT has 51 reviews with 92% positive. Both games are psychological horror adventures as well as upcoming The Human Gallery. I'm guessing these games would be "too niche" for GOG at the moment due to poor sales on Steam but i'd love to see them here one day.