Lovely visuals! And I love architecture I can climb around on. I'd have liked to have been able to go inside the towers, though. Even just in passing. It would make them seem more 'real', rather than just overly large pedestals for the items on top of them. Here are a few ideas how to do this:
GL Tower: As in the screenshot below, simply shift the player's route along a bit. All it really does is incorporate the tower a little more, but I think it would be suitably effective. The only problem comes with the stairs, as they now collide with the path of the next set which is bad map Feng Shui.
RL Tower: Again, see the screenshot below. A barred archway, leading to a room containing the RL and a yellow armor or mega health. The bars would only open from the inside, and the room would be accessible by the teleporter that's currently used for the quad. If this were to happen, that teleporter might benefit from being made a little more obvious/accessible.
Quad Tower: A staircase joining the quad tower and the RL tower would add a sense of conectivity to the design. As it is right now, I find the towers feel very far removed, or disjointed. Following on from my previous suggestion about the RL tower, the teleport to the quad would now be right beneath it, making it a much more trecherous experience to get it as people can watch you teleport up there, then trigger the trap. On the subject of the trap, I think some sort of visual/audio representation of it working would be helpful, as I spent a long time shooting the button and wondering what exactly it did. Then of course, I went and shot it from the trapped area and found out. : P
Whether you go ahead with any of those suggestions or not though, I certainly think the map needs one well placed red or yellow armor [unless I just missed it?] to add a little purpose to the player's route.
I too had the void problem when I fell down twice in quick succession. Would it be possible to put a trigger_multiple with 0 delay down there to turn on the trigger_hurt? That way, if it doesnt get you the first time it'll just keep triggering until it does work.