the corridors were too narrow. Also, i'd have liked some more view of what was going on in the center. The doors felt off, but i'm just an arena noob. though i would have liked some mid-level acess to the room. You have the potential for an awesome layered battle here, but the closed doors split it into a fight at the top, where you cant see things because of the curve, and a battle at the bottom. The bottom and the lower level are cool though.
Also, the arched walkway felt odd to me. like i was in a flying trench or something, maybe it would be better flattened out, or with a barrier like the lower level.