Google Music is not yet implemented. There are workarrounds, but none of them as elegant and simple as Rune audio itself is.
But I suggest you donate anyway, as Rune is a beautiful enthusiast project not a mega company spin off and all inentives are highly apreciated. Plus that will be a big pat on your karma's back! I am sure.
As far as I know guys have the integration of various streaming services planned along the road. For now sadly only Spotify (which alas is not available in my country) us experimentaly integrated, there has been talk about Tidal and others (like Google music all access), but there is no date on that yet.
