kohlrak: I assume you do have the client, so i just added you as a friend. I'm going to start a game that i'm sure is galaxy friendly, but without using the client. Let me know if you figure out what game it is. Starting it before you even read this post.
MarkoH01: I doubt it will work this way. As far as I see it the one playing the game has to use Galaxy for it while the other does not need to use Galaxy. But while we are at testing we could just continue seeing what happens :)
Edit: GOG website says that you are offline just as I persumed.
THen you predicted correctly, because Tangledeep is running right now. I assumed you meant the other way around, which, i would have seen as a huge privacy violation on the part of gog, but a popular one (every console and service anymore wants everyone to know what you're playing to entice them into buying it, but then things like huniepop would be bought much, much less [I was tempted to try "senran kagura," but then i realized everyone in the world would see me playing it on my 3ds, for example, which is not something you set yourself up for]).