However, there are always those of us with fond memories of 1993 and the original Doom game, and just going around... well kicking ass. When Doom 3 was released, I decided to try my hand at mapping. I had no idea where to start so I figured I do something relatively easy by today's standards - the angular corridors of The Ultimate Doom's E1M1. So I did, and I enjoyed it. I finished the first version of it, and saw with the knowledge I had developed in the process of making it, that it was pretty bad. So I remade it. Scrapped that and remade it again. I developed this version and as I developed it, I changed things about the game and turned it into the basis for a mod.More info and download link over here.
Play Doom with Doom 3 mod

A new Classic Doom mod has been released last week for Doom III. This mod recreates the original Doom in today's technology and people who have tried it out are very pleased with it.