Great map!
It's pretty obvious that the map is designed quite nicely, it has a good flow to it with plenty of height variation for interesting gameplay and the weapons seemed to be nicely placed. Visually, the visual style was nice and consistent and the level was quite detailed/noisy which is good. Although I could think of a few minor things I would change, such as those large round open pipes suddenly ending, I've never been a fan of those sudden black walls. I think a grate the player can see through and the pipe fading into the darkness or a curve in the pipe adds depth to the level and may generate curiosity in players "hmm I wonder where this pipe goes if only I could go behind the grate", as opposed to feeling cheated or ripped off by a trick to perhaps save some polygons or the level designer's time.
When watching the youtube video I was pretty skeptical about this whole energy cell thing. In this sort of map (arena styled I suppose) I thought that with a decent amount of players, gunfire would be coming from all directions and it would be too difficult to try and manage finding the energy cells and using them but after playing around in the map by myself for a bit, I can see how once players become familiar with the map this mechanic could become pretty central to the gameplay on the map or at least influential on the gameplay to some degree.
One other thing.. I thought sound design in the map could have been better. Like you had sounds in the map and they did enhance the map but not as much as I think sound could have potentially enhanced the map.
But overall this is a really nice map. Good stuff! 
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