Adarion: Not yet since I am also confused and waiting for a release on GOG. You can buy it DRM free for months now on humble.
I played Expendabros which is likely close to a long demo. And I really liked it. They're not taking themselves too serious, obviously, it is relatively fast and fun gameplay, nice old school graphics (reminds me a bit of what I saw in terms of NeoGeo back in the days), controls are fine, difficulty is okay and you kind of have unlimited lives.
It's supposed to run on Linux, too, so I really want that game. If it doesn't show up on GOG I'll probably have to purchase from the people directly or from the humble store.