Wow this game got big fast without even being released yet. I just saw it the other day around the indie game dev community. They are really doing good with marketing. Also I find they did very well with the art style. It is simplistic but has style.
This seems to draw a lot of influence from Snow Crash, judging by the quick look, which is exciting for me. We don't see nearly enough absurdist narrative.
It's shorthand. You and everyone else knows very well that it means "recent versions of the operating systems descended from the IBM PC and the Macintosh."
The IBM PC is strictly a hardware platform. Macintosh was also a hardware platform but the name got associated with the hardware-OS pairing even after the OS's name lost the "mac" particle. Modern "macs" use PC compatible hardware.
Anyway, what I'm complaining about is the habit of naming hardware platforms with the understanding that they probably run a certain OS on them. In this case it looks like Linux is supported, just not advertised. The sooner we kill this confusing marketing jargon the better for everybody.
I made the mistake of watching it at around 2AM, so hopefully my uncontrollable laughter didn't wake up my neighbors.