Back in January 2016, John Romero released a new map for the classic Doom. That map, titled E1M8b, was a replacement for the original E1M8 created by his co-developer at id Software, Sandy Petersen.
A few months ago, Romero released a walkthrough video, explaining the design behind this Doom level.
As Romero noted, at that time he was practising level design and wanted to start with something really simple as Doom, and release whatever he made.
This map features a lot of references from some other levels from the first episode of Doom, as well as references to the Star Wars movies and the Star Wars: Dark Forces game.
It’s a really cool video that will give you an idea behind the creation of this map.