They're (very) loosely based off the first six maps of DooM 2, but in the style of E1. The maps themselves are vanilla compatible, but I have included some custom flats, so the wad won't load with some ports (the only port I've tested that doesn't work is Chocolate Doom, I assume the originally exe too, but dosbox and me have a complicated relationship, so I can't confirm this).
I've also included a scrolling parallax sky, for ports that support zmapinfo. (I tried to get it working with other source ports using regular mapinfo, but without success. If anyone could help me understand what I've done wrong, it'd be appreciated!)
Map01: Service Access

This was made about a few months before the rest of the maps, and is probably the weakest of the set. It's probably also the most faithful to the original, since most of the areas, and progression are the same, just being aesthetically different. A lot of the previously optional rooms are now required, though.
Map02: Coolant Loop

This was the map that really kicked off this project, since for me Map02 is the map that I always associate with DooM 2.
Map03: Reserve Reservoir

The first map that significantly departs from the original. Be aware that progressing through the map does lock you out of some of the secrets.
Map04: Canal x05B

A lot more outdoorsy than the original, but follows a very similar progression.
Map05: Secondary Exflow

Map05 is the first map from DooM 2 I don't particularly like, so this one's quite significantly different. I think the progression is still recognisable, though.
Map06: Datum Centre

I played around with the progression on this one, to ramp up the difficulty of each encounter, and make the centrepiece something you have to fight to, rather than just being right at the beginning. You'll want to save your plasmagun ammo for the last fight... you did find a plasmagun, right?