Super MAYhem 17 (MAYHEM17.WAD)

MAYhem is a time when Doomworlders can band together and throw their weight behind an arbitrary set of restrictions. The series had a rough start in terms of meeting its megaWAD goal, with 2012 and 2013 fielding 12 and 11 levels respectively, but it hit its stride with MAYhem 2048, with each subsequent iteration meeting the "megawad" definition (in spirit with MAYhem 2024, which produced 35 segments to stitch together). The 2017-released-in-2018 installment goes by Super MAYhem 17 because the texture theme this go-around was Super Mario Bros.-themed, with an aesthetic that appears to be sort of a mix of Super Mario Bros. 3 and Super Mario World. This is a 28-ish level replacement for Doom II, to be played with Boom-compatible ports, with some fringe MAPINFO perks for ZDoom / Eternity users.

rf 1024 (RF_1024.WAD)

Exquisite Corpse begat Congestion 1024, which begot the now maligned 1024 fad of Doom mapping. fletcher` was on the train back in 2006, adding an additional constraint. Now, ten years later, they've created a whole megaWAD for ZDoom and Eternity (make sure you have infinitely tall monsters off) - rf 1024. If you didn't already know, the premise of a 1024 map confines the area available for player movement to a size of 1024 by 1024 map units. The map itself could be as big as you wanted, and indeed many 1024 levels involved copious amounts of teleport coffins to turn a tiny level into a full-fledged slobberknocker, or various ledges and elements outside the playing area for detailing, world-building, and monster perches.