Duke Nukem 3D was built on the 'build' engine, which was built by a super cool 18yo called Ken Silverman http://advsys.net/ken/ .

Back in the 90s John Carmack was asked "If you could just hire anybody from the 3D world, who would you hire?", and he named Ken http://advsys.net/ken/carmken.htm

John Carmack, Ken Silverman and Tim Sweeney.

The three legends / rivals of their time (but with mutual respect)

Thanks for the link! This really took me back to the games I grew up on that influenced me (haven't heard the names ROTT or Redneck Rampage since the 90's)

At the time, going from quake to glquake felt like a huge leap in technology. How could graphics even get any better? I guess every generation goes through something like that.

Have you played the remaster? It has a lot of subtle upgrades (and more polygons of enemies is one of them). It's really good.

I also loved playing Tenebrae Quake on the Mac. Not sure if it's still around though.

It's not, but the DarkPlaces engine [0] reimplements many, if not all, of the realtime shadow features and has an X64 Mac build (but no ARM build, as far as I'm aware), and is still getting active contributions on its Github repo[1].

[0]: https://icculus.org/twilight/darkplaces/index.html

[1]: https://github.com/DarkPlacesEngine/darkplaces