Abaddon's Nightmare is a large, somewhat lengthy (I can complete it in about 13-17 minutes) and difficult map for GZDoom.
Originally, the plan was to create something similar to Plutonia's map 12, "Speed", but that turned into both a proving grounds for everything I've learned about using Doom Builder, Slade3, etc. over the last few months and to experiment with lighting and design. Some of these work a bit better than others, in my opinion, but I'm happy with how everything turned out. Much of the map was not pre-planned and what little was ended up being changed as I started plotting it out in DB and adding details.
I've used various textures and 'things' taken from the packs available on Realm667, to whose creators I of course give full credit and thanks, but the gameplay is completely unchanged. The map also features a lot of work on the lighting in a few parts so I'd recommend playing with the software renderer for maximum spookiness. I also only ever play with both mouselook and jumping turned off, but using them yourself shouldn't break anything (I hope).
I hope you enjoy the map and I'd love to hear your thoughts, both the good and the bad. Gameplay-wise I'd say its pretty difficult but I tried my best to make sure everything was fair. Keep an eye out for secrets, traps and enjoy the archvile.
The song is Baron's Province by James Paddock