[Comments written as I explore the map and find things]
-You should probably add more playerstarts than 5
-Where there is a health by a break in a low wall, the wall is a bit crumbled but the floor isn't. Maybe the edge should be a bit rough there
-The tunnels look very boring, even with the green supports.
-You've obviously noticed that some parts of the pipe you can't get into can't be seen, but they should probably be skytextured instead of default or other random textures, unless that creates weird lighting from the skylight.
-although you've clipped off the level pretty well, I think it would be nicer if there was more room vertically so you can launch across the map without hitting the invisible ceiling.
-the small vertical pipe sticking out of the wall near the big blocked off pipe doesn't really need to be noclipped. it's wierd to be able to jump right through it.
-there doesn't seem to be any reason why the conveyor belt at the bottom of the map kills you.
at the least adjust the deathclip lower so that you actually hit the conveyor belt before you die instead of dying in midair when jumping between the struts directly above it. (you did intend that players can stand on the struts above it to get the healthboost, right? You currently can)
-i'm not an expert at pickup placements, but 2 yellowarmors seems excessive. I'd make one of them green at least.
-I only found one of the teleports, and it seems completely unnecessary to the map, as it the out-of-the-way platforms it's on [nevermind, didn't notice the second one at the healthboost, that one seems okay though]
-also, there's probably a better skybox you could use.
5/10 for now
edit: Oh yeah, I meant to add that there's probably a better name too, but RaGaRiZ beat me to it
