E1M1, Episode 1 - Map 1 in the original Doom is designed by John Romero and is the beginning of a new era in first person and 3D gaming level design. It is the first level to greet a new player to Doom and it is now very famous for that very same reason.
The level itself is very short (par time: 30 seconds) and very basic, learning you what you need to know about the guns, the pickups, secrets and shooting stuff without forcing you to think too hard about it.
You start out in a small room with 4 pillars, some health vials and some armor bonuses. Next to this room is a small circular room where you can see the skybox outside. In the same room is also a pillar with your first important switch. The level also features some other memorable rooms that quickly comes to mind for many old school players who have fond memories of this particular level. The big "technological room" with huge monitors hanging from the roof, the big outdoor area with an armor pickup in the middle of an acid pit and the room with the big window, a "Z" shaped walkway in the acid and imps shooting down on you from a "secret" ledge are just some of what E1M1 has etched into our minds.
This map is also very famous for its music though. The track for "Hangar" is created by Robert Prince and is based on Metallica's "No Remorse" verse wich says alot about the team's influences at the time. The team at the very young ID Software, and in particular John Romero, was listening to alot of Metal like Pantera and Metallica while coding well into the early mornings. This particular track has put alot of the other tracks in the soundtrack somewhat in the shadow and has become somewhat of an icon for midi guitars from the 90's.
There are alot of historical information out there explaining what this level meant for the young John Romero and John Carmack with the book "Masters of Doom" standing out as a very interesting and important read for the interested gamer!
The first part of this level is now also an easter egg level in Rage !