What ? Galaxy is optional. All their games are DRM-free.
GOG has their own galaxy client which at this point is almost better than steam. Just as comfortable, you do not have to mess around with installers.
Wasn't on about galaxy, although their latest stunt of wanting to install an installer for galaxy into offline installers was dumb enough...
A few of their games do have some DRM problems. The latest Gremlins game was one of them from what I've seen on the forums, along with a few others.
There's a gogmix list of them all, will link if can find it at some point.