It should almost go without saying now that Doom 2 is all things to all people, in the most literal sense. Thanks to 25 years of evolution in modding tools, it's Donkey Kong, Resident Evil and even Heroes of Might & Magic now, among other things.
The latest game to be swallowed by the all-consuming vortex of creativity that is the GZDoom-powered mod scene is Quake Champions. The arena FPS reboot may still be in public testing, but it's already been systematically disassembled, stripped for parts, and launched today as Quake Champions: Doom Edition (or QC:DE for short), a mod for possibly the most enduring game in PC history.
The latest project led by prolific modder DBThanatos (his previous work, Doom4: Death Foretold, mashes together 2016's Doom and its old-school predecessor to spectacular effect), Quake Champions: Doom Edition isn't so much a direct clone of the still in-development arena shooter, but rather an adaptation of many of its core concepts, plus a sprinkling of fun new ideas.
Probably the biggest departure from Quake Champions' design is the option to play both in single-player and co-op mode on almost any existing Doom level you can throw at it. Players use the full arsenal (12 weapons mostly from Champions, 13 characters from across a wider range of games) against a bestiary of monsters lifted from Quakes 1, 2 & 4; 3D beasties surprisingly well adapted into 2D sprite form. The description panel on the above trailer includes a long list of recommended levels that pair nicely with the mod, and I'd personally recommend The Ultimate Torment & Torture, which already has a very Quake-like aesthetic.
That's not to say that the competitive side of the mod is going to let anyone down. Fully supporting Zandronum (a GZDoom variant designed for online play), QC:DE launches with a collection of 40 deathmatch maps: 7 exclusively designed for the mod and 33 adapted from AeonDM, an award-winning community collection of multiplayer levels featuring some of the best talent in the scene. If you don't feel like going online and getting fragged by total strangers, no worries, as QC:DE also has full bot support. Even if you do plan on going online, it's a good way to learn the maps before jumping into the fray.
QC:DE is out now, and can be downloaded from ModDB. You'll need the main data WAD file from the original Doom 2 (available on Steam, GOG or elsewhere) plus the GZDoom or (for multiplayer) Zandronum engine to run it. The official Discord channel for the mod is also hosting a launch party, directing players to organized, moderated servers for ultra-violent fun times.