Literally maxes out the capabilities of the current version of the engine.
The mark of a great game is how long after the fact people will continue playing it. It’s been over 20 years, and people still play Quake. And now, the ultimate level has been built for Quake: The Forgotten Sepulcher.
Ostensibly a remake of a classic Quake map E1M3: The Necropolis, The Forgotten Sepulcher may well be the most detailed Quake map in existence, possible ever. Built by Simon “Sock” O’Callaghan and Henrik “Giftmacher” Oresten, the level actually pushes Quake well beyond its normal limits. So far beyond them, in fact, that it literally only runs on two heavily modified versions of Quakespasm and Quakespasm-spike.
https://www.youtube.com/watch?v=K8JWgsz8-lQ
The map was initially designed by Orestein, a Swedish schoolteacher by day. He’d been following O’Callaghan’s work on Arcane Dimensions, a Quake mod/campaign, and decided to take a crack at level design himself. That, in itself, started a working friendship between the two.
The Forgotten Sepulcher is massive. It features 60,000 brushes (a Quake term for individual shaped blocks). To give a bit of perspective, the original level it’s based on is roughly one sixtieth of that. It features nearly 300 monsters, sub bosses, around 90 secrets, destructable portions of the environment. Hell, it’s such a large level it actually provides openable shortcuts back to the start ala Dark Souls.
To play the level, as well as others by Simon’s team you (of course) need to own and install Quake. You’ll also need this version of Quakespasm and drop its files into your main Quake directory, and make an “AD” folder in your Quake folder and drop Arcane Dimensions into it. You’ll also need to Download ad_sepulcher and drop its files into your AD folder. Then you just run it from the Quakespasm shortcut, go to mods, and select the “AD” folder. To actually play the level, you need to take the leftmost portal, then head right from there.