1) The flow of the level feels good. I could bunny hop around and keep a good pace up.
2)The environment look and feel.
3) Enemy placement feels good.
What I would change:
1) Add player clip to the stairs so it is easier to bunny hop up them. (pet peave of mine.)
2) Frame rate! There is a lot of overdraw in the long hallways. I run a P4 3ghz, 1gig ram, 7800gt card and was seeing 15 fps at 1024x768. I would aim for 35fps with combat going on.
3) Where the glass meets the tile on the floor I would put a metal frame or trim of some kind. It just struck me as odd.
4) The bathroom and closet. If you have dead end rooms, give the player a reason to visit them. I would put in some pick up items (health, ammo, etc..) or maybe put in a health dispenser. Playing the level, once I realised they were dead ends I never went into them again.
5) The Dopefish should make an appearance out in the water.
I didn't really look for him so if he is already there forget I said anything.
I dig the map so far. It's fun.