It's been saying that for months, and there has been no status update at all. At this point, I wouldn't be surprised if Galaxy on GNU/Linux is vaporware. How could it take so long, and still not even have a beta (or even an alpha) release? Obviously it's just not a priority for them.
It's not just the delay and lack of communication that's frustrating, but the way they're treating GNU/Linux with their http://www.gog.com/galxy
page - GOG checks your user agent, and *actively hides* the Windows installer download from you! How evil is that? Scroll down the page and the "Download Galaxy" icon appears, but clicking it just scrolls to the top of the page. And it's been broken like this since Galaxy launched for other operating systems on day 1!
Think about it; if GOG hasn't figured out their download page doesn't work in GNU/Linux after all this time (eg. for people that use Wine, or even people just expecting a working link), what are the chances of them releasing an actual GNU/Linux client?
And if you actually do view the HTML source and extract the Windows download link (or use a Firefox add-on to make the website think your GNU/Linux browser is a Windows one), and then report a bug against it - clearly indicating that you're using Wine and that the fix would be trivial for GOG to make? They'll just close down the ticket. No "we'll take that under consideration" or "we'll keep it open but give it a low priority" - no, they'll just straight-up close it.
If this thing ever does get launched (and I'm not holding my breath), I hope to God they're not planning on installing games via deb packages. I love debs, but the way GOG expects people to use them is about as unsafe, insecure and impractical as you can get. No use of repositories, no GPG signatures, sets insecure permissions, manipulates the contents of user files under /home, doesn't uninstall 100%, wasn't even built properly (ie. did not use dpkg-buildpackage as per the Debian packaging guidelines)... and they want people to trust these with root? These things are never okay. They should have hired someone with a clue! I know that sounds harsh, but it's the truth. The debs shouldn't be distributed in their current form. They need to be removed, and they certainly should not be a consideration for Galaxy.
Not that we'd know of course. If it's does ever get released.
Not sure why they hid it in the first place, maybe to avoid confusion about the less tech savvy customers? Still it would be no excuse to hide it from us, placing a warning notice would have been better.
For whoever's interested here's a direct link (so you don't have to waste time setting up a Windows browser in Wine):