How "hard" is the requirement for Win 8? What does 8 have that is required that Win 7 64 bit doesn't have? Has anyone tried it on 7?

Yes, it works just like on the other systems. This requirement is probably because GOG partnered with Microsoft and they are known for forcing users to install W10 (and for that I'm never installing it). I would love to know that.

thanks; I'm just trying to get 2.0 to run on my system and I keep getting the error that Galaxy is already running, even if I completely restart windows.

Windows 8 is end of life and Gog made a typo... it should say Windows 8.1 which is a different system to 8

the main difference between Windows 7 and later models is Ram, latter versions of Windows NEED a lot more Ram than 7 did and that is because apps \ programs are loaded into system Ram during use to improve performance

yes people have got Galaxy 2 to install to Windows 7... no its not going to run well unless you force feed it Ram and even then expect issues running it in the background while you play your games

with your Galaxy is already running issue [see screengrabs] i would look if you have it set to autostart... untick the option

No

@OP: The reason is that Windows 7 has passed its offical support date, thus gog (as any other company that sells software) does that too.
That does not mean it won't run on Windows 7, just that gog refuses to give you support if seomthing does not work.

Oof maybe the problem is that Galaxy is a memory hog and uses 10 times as much memory as Steam? And what's with the high CPU usage? I'm starting to question going with it instead of Steam now

you do whatever makes you happy mate