Let me start by saying I hate Q3 style maps so you know where I'm coming from.
This is very similar to one of the maps that shipped with the demo.
The textures....
imo use more variety. You've got one blah texture everywhere. You can certainly use something more interesting on the floor, some trim on the lower walls and then something else on the walls to give it a little more zest.
The kickers...
I found when jumping to and from the shock rifle area I'd loose health. Maybe decrease gravbity just a little bit. I'm not sure if that effects kickers height as well.
Weapons...
Mini gun rules this level. Loque with mini=dead me.
The main qualm I had was why do you need to put yourself on a limb to get the shock rifle. It's very dangerously placed and I got killed 5 times before I managed to get my hands on it.
Especially because I didn't find the shcok very useful here. The spaces are too open and if you're going to combo it leaves you open to somebody with the mini or hitscan as there are no places for cover.
I'd switch the shocks with the mini gun..as that is a more potent weapon in the areana.
Skybox...big black void? You can do better. Put in a super cool skybox or something. Adds to the experience