I forgot to mention in that video that the Steam version doesn't have the music, which is a crime (although the GOG version supposedly does?).
Google for Ultimate Quake II patch and you'll get a package that has .ogg versions of the music that works with the Steam version, although it also forces you to use a sourceport with different UI and more modern graphical effects, so you aren't getting a totally pure experience.
I actually fished my original Q2 CD out of my fuckoff huge CaseLogic CD binder in the closet and threw it in the drive, and was pretty impressed that the Steam version just picked it up and played all the music like it should with no tweaking required. The Carmack difference.