Not Bad For Your First Map, I Guess...
Heh, actually it's great. Thank you for this fine trimwork - may it serve as an example for other mappers.
Good layout and detail. Though you really could have fixed the textures on the upper sky bits (beige non-detail tex vs unaligned wall tex) for the holistic thing.
I don't like cop1_5 - it's a blurry version of cop1_4 and looks weird next to normal textures.
Gameplay on Hard was fun, if not a bit predictable in some areas (but it's okay). Also, OMG hacks!
A few zombies for relief gibbing would have worked well, too. I wouldn't have minded an occasional shambler or vore earlier on, either. No SNG and GL seem to work here, but I can imagine it might get tedious for some players after a while.
Nice secrets... meaning easy enough that I managed to find seven (plus the useless one afterwards). The pent should have been something else, in my view. GG for the signature/easter egg intermission.
What I find most impressive is how seemingly fast you made the map. Seemed like a matter of days, or maybe two weeks, not months or aeons like other people (including me) would take for a map of this size.