This map replaces E1M1 of HERETIC. It has been tested to be beatable in all difficulty levels. I even tested it myself on "Black Plague" and can confirm that it can be finished (albeit with a LOT of save/loads).
I have disabled crouching and jumping, because their use can and will break the level. Also, I recommend going to options > display options > message options, and setting "scale text in hi res" to on, because there will be messages that you need to read in order to finish the level. If you have trouble with the puzzles, even after viewing the messages, scroll down to the bottom of this text file for the solutions.
Rich Nagel (www.richnagel.net) for his excellent music (I used 2 tracks from Eternal DOOM soundtrack), Toes for her texturing and detailing ideas, Gez for some serious lessons in DECORATE, the Doomworld and ZDoom forums for giving me good advice and being helpful and encouraging, Tormentor667 for continuing Realm667 for the good of the community, Hexen for the awesome sky texture, Raven software, and ID Software.