I can agree with almost everything v1|3 and AEon had noticed, I even like your map because of the same motifs (q3dm6 feeling, the 90° ascending stairs, and so on).
About the pool: you can put a MH into the water to make it worth the time and thus risk to get out of it again or simply use "cushion" clip if it is just about falling damage that should be prevented.
Just interested: which build cmd did you use to compile this map?
The big room from the top to the bottom with the quad power-up seems somwhat crowded if playing with 4 bots on nightmare (hi there hardcore-AEon!), since they tend to be there all the time and neglect other parts of the map. But that could just be me playing against four nightmare Bittermans

. I still recommend to do that to everyone else reading this: these suckers will start their own personal rampage with really nothing but grenade launchers (well some other weapons too but GL is chosen like 80% of all the time), this is one of the funniest dm I've played in a long time.

(compare with screenie #3)
Now for the rest of the feedback, brightly pictured, with my notes directly in the pics (quake chat,):
All in all a very nice death match (yeah, forgot to set a time and fraglimit, gave myself 12 minutes to get acquainted with your map, didn't have the same problem as Aeon did, maybe because I didn't use the teleporters too often, might have taken another 5 minutes then):
