The past is a different country. You look at a level like this and wonder, so how did people play Doom back in 1994? Because believe it or not, this was intended primarily as a deathmatch level. That warren of narrow, near dark passages with tons of corners, grids, junctions and alcoves was apparently just the thing for playing with your friends. Still, I guess if the main thrill you get out of a deathmatch level is trying to hunt down/hide from your opponent, this level at least offers you that pleasure.
I found it fairly trying as a single player challenge. That labyrinth at the start has about a dozen monsters in it that wake up as soon as you make a noise, and you've got to go and do other things like get keys and weapons, so you can't control where they're going to wander. I had a lot of luck in this run, nearly all of them came straight to me as the invuln was running out. I know some other parts of the level look less than optimised, but when a huge part of the level is completely out of your hands as to how long it's going to take, I decided I'd take what luck I was given.
There's a few minor weird things. One spectre is carelessly placed so he's stuck in the passage wall - I make a quick detour to kill him at 1:45. And the BFG secret has a teleport line in front of it, but it doesn't always work for some reason. I need the weapon and I need the secret, so that's why it took two tries to get.