Lithubristics Under Sanguine Twilight is PasoconDeacon's first full map, a 25-to-35-minute trip for you and nearly a month of bashing his head against Doom Builder X to get what he wanted. 

• Doom II-based MAP01 replacement, comes with BEX patch to alter automap name. plus new intermission graphic.
• Boom-compatible, play with complevel 9.
• No jumping or crouching, designed/tested without freelook.
• Use software renderer for best lighting!
• 25-/35-minute map, tested without saves, features some exploration and plenty of combat.
• Balanced around Ultra-Violence, includes some changes for lower difficulties; difficulty sits around early-2000s WAD range (mid-to-late Alien Vendetta, Scythe, Plutonia-equivalent, etc.).

Check the thread over at Doomworld for the second release candidate and some futher information.