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.

1 Monster (1MONSTER.WAD)

We are more awash in limitation-based projects than ever, with 10 Sectors capturing the imagination of the community. When 1 Monster was conceived, Dr. Zin had 2 Sectors and Congestion 1024 in mind, though we've since seen 100 Lines and a whole host of resource-economy projects. What you don't see a lot of, though, are restrictions on enemy variety. Enter 1 Monster, a megaWAD where only one monster type is placed on each map. Every member of Doom II's bestiary is represented here, from the lowly zombiman to John Romero himself with his luscious locks of love. The project kicked off at the tail end of 2005 and then changed leads several times before seeing a final release in 2007. In its more or less final form, 1 Monster is a 25 map replacement for Doom II, to be played in Boom-compatible ports.

MAYhem 2012 (MAYHEM12.WAD)

The good news is that TheMionicDonut's MAYhem became an annual institution where mapsets - sometimes a megaWAD's worth - are created. The unfortunate news is that its completion / polishing phase inevitably runs over the monthly time frame. MAYHEM12, for instance, saw its final release in November of the same year while MAYhem 2013 hung around until March of 2014. It isn't much bad news at all, though, especially considering how long projects usually languish on hard drives. The community still gets a brand new collection of levels to play and the contributing authors get to flex their muscles in a theme that they might not have otherwise experimented with. In this case it's twelve Boom-compatible levels for Doom II.

Mayhem 2048 (MAYHEM14.WAD)

Mayhem has been a Doomworld institution since 2012. TheMionicDonut had a dream, and that dream was to get as many people as possible to make a map over the course of a month - May, of course. The other part of the institution is to take as long as humanly possible compiling and fixing the darn thing, with 2012 seeing release in November and 2013 in March... of 2014. As of the time I'm writing this, the 2014 installment - Mayhem 2048 - is still not finalized, but maybe by the time this is published they'll pull together and slap the thing on the archives (EDIT: done as of Nov. 27!).

Hadephobia (H_PHOBIA.WAD)

Hadephobia started a long, long time ago under the banner of "Progressive Fiction". It was something of a conceptual community project. Basically, someone started by making a map, writing a bit of a story to go along with it, and then passing it on to the next person, who would do likewise, and repeat until they had finished a full-fledged Doom II megaWAD for Boom-compatible ports. The story is a little scatterbrained at times as far as the finer details, but the main idea should seem familiar. After all the agony of the Doom games, you continue to have nightmares, some kind of psychic link with Hell which dubs you as a Hadephobe. The bad dreams start to get even worse and you're sure an invasion is imminent, but the UAC locks you up in a distant asylum, out of sight and out of mind. You're the boy / girl who cried Doom, though, and when another invasion breaks loose, you must fight for your life.

1994 Tune-up Community Project (1994TU.WAD)

The 1994 Tune-up Community Project started with a simple concept. The general opinion of WADs from Doom's earliest era is not glowing; most 1994 maps are considered crude by today's standards. The disparity in appearance and playability is attributable to any number of sources, but Doomworld forum superstar Snarboo presented an interesting idea for a project, assisted along by GreyGhost and Travers Dunne. Rather than bitch about how awful '94 WADs are, why not take the ones authors released free to modify and renovate them? The target was limit-removing and Boom-compatible, freeing mappers from the dreaded visplane specter and allowing for a limited number of "advanced" features. The only caveat was to avoid rendering the layouts of the original maps unrecognizable, though contributors were free to make their own additions, provided they not increase the map's size by more than 100%. As a general rule.

Doom 2 Unleashed (PC_CP.WAD)

Paul Corfiatis is a veteran Doom mapper, the author of ancient WADs like The Twilight Zone. Upon releasing his Whispers of Satan megaWAD with best Doom buddy Kristian Aro, he opted to start a community project, which debuted in 2011 as Doom 2 Unleashed. It's a forty map megaWAD whose last eight levels constitute their own episode, titled "No Hope for Peace". The scope of the project was restricted to maps that functioned in any limit-removing port and used only stock Doom II textures. I'm not entirely sure how the bonus episode is handled outside of ports that support maps in excess of 32, let alone custom episode definitions, but in ZDoom NHFP shows up as a selectable episode, backed by the soundtrack from Inferno.