I've got it through GOG and haven't had a single issue with Galaxy yet. The pre-load was fine, it had to update about 50 MB when release day happened, and then the big 580 MB patch smoothly updated within a couple of minutes of me exiting the game yesterday.
Hm, I have to admit, the Athletics skill feels buggy experience-wise. I'm constantly running / sprinting to places and jumping up and around, and after 30 hours of gameplay involving lots of that I still haven't got my skill up to 4 yet. Compared to the others, which are (for the majority) nearly double that.