Caverns of Darkness.

Just need to get this off my chest. Really good effort on this mod, but... I hate map03.

You are not alone in that regard. That map is truly annoying.

Not counting the Sub:PAR stuff released with P:AR, Map03 is undoubtedly the worst map I've created (at least, I hope so...anybody think a particular mpa of mine is worse?) Still, I think it is in some ways novel, and certainly provides a different type of gameplay than most other Doom maps (and certainly the other levels of CoD); the same style-change philosophy was used in the 2nd secret level ("The Stand"), but apparently that worked a lot better.

In retrospect, perhaps some elevators that rise after you pass some key points so that you don't have to backtrack through the whole upper level if you fall might have helped. Or, perhaps it's just a steaming turd-pile. I don't know. Still, "Railbender" (the train) from P:AR was similar in that you have virtually no space in which to move, and people seemed to like that...

Lutz said:

In retrospect, perhaps some elevators that rise after you pass some key points so that you don't have to backtrack through the whole upper level if you fall might have helped.

That would have helped a lot. Not wanting to backtrack for each small mistake I make I normally save after every difficult jump so I can just reload. If might also have been better if the level wasn't so unhealthy in its design... ;)

Still, "Railbender" (the train) from P:AR was similar in that you have virtually no space in which to move, and people seemed to like that...

That's because:

1. It more resembles a real location.
2. You aren't punished that much for your mistakes.
3. Unlike CoD Map03 it was an interesting idea to make a cramped train fight.
4. It is just a great looking level.

I don't mind platform levels in general but combined with a damaging environment, a Revenant you can barely see, a bunch of Lost Souls you can also barely see and a monochromatic look where you can barely see anything made it a chore.
Railbender is plain fun in comparison (and The Stand is also significantly better.)