Nice, I'm surprised it took this long! My first experience of playing Quake 1 in my home was an unauthorized source port which ran in System 7, I believe was called "HackQuake", ported from stolen source code from CrackDotCom apparently[0][1] .. For me as a kid getting insanely impatient to play Quake, this was a godsend! Even if the performance was brutal and firing a rocket caused the framerate to halve. Played it at 320x200 pixel-doubled just to eke out that extra little bit of performance. Anyway, the point is that HL probably could have been running on Mac since day one, if someone had spent the time to port it!

[0] https://www.wired.com/1997/01/hackers-hack-crack-steal-quake...

[1] https://github.com/Jason2Brownlee/QuakeOfficialArchive/blob/...