The Abyss (ABYSS.WAD)

The Abyss was rescued from... the abyss of time. It's crazy to think that the primary reason we have The Abyss right now is because one of its creators, J.M.P. van Waveren ("Mr. Elusive"), toted a copy of it with him when he started working at id Software. Otherwise, who knows? This megaWAD was released over several iterations, eventually crystallizing in 1995 as a 24-map replacement for Doom II, not counting the placeholder "THE END" levels. Miklos de Rijk ("H2SO4") and van Waveren originally published The Abyss on a more localized BBS in The Netherlands, but there's no digital record of anyone acknowledging it. de Rijk and van Waveren went on to significantly more acclaim with their Omicron Bot for Quake, notable for its apparent ability to function on "the jankiest, boxiest of community maps". This apparently got Mr. Elusive a foot in the door at id, where he worked on Quake III and subsequent projects before following Carmack to work on the Oculus.

Riot Control (RTCTRL.WAD)

Riot Control is a four-map minisode for Doom II and Boom-compatible ports by Doomworld forum superstar Ronald Lubellinkhof, aka "Dutch Devil". The project started out with him playing around with textures from the original Quake, only intending to make a few maps, but he was inspired enough to round the set out at four (the whole set produced over more than two years). They're not very long, with even the largest of the four feeling medium at best, and not too terribly difficult, the main limiting factor being health. Dutch has included no story, with the action speaking for itself. You're a marine infiltrating a series of outposts located in a mountain range.