Hellfog,
Anyway, I tried using Kell's skyboxes and played around with shader light settings for a long time. It looks okay on my computer but the screenshots are really red. I may just go back to the default id sky map because I like the lighting it gives off.
About skyboxes... alas all the tutorials I tested, e.g. also -skyfix only lead to an overlap at the skybox edges. If the skybox actually *has* the same 2-3 pixel rows on every side things will probably work. But all the really cool skyboxes, like those by Hipshot, alas never worked properly on my ATi X800 either.
If the colors of the sky are weird, look into the skybox shader, and change the color of the sky to a more pastel color, to avoid color saturation.
A few people have mentioned jump pads and I wanted this level to be jump pad free, but Aeon is right about the ledge, it is fun to be up there but hard to get up there. The teleporter actually teleports you to the ledge in the open area, but unless you pull back you fall into the lower area.
I had been thinking of pulling back a wall where you respawn, much like in the first shot you posted. And I had thought you could possibly place a 2nd teleporter up there in the edge area. That would make a complete teleport loop. Might be interesting...
Shot 1
Looks nice. I was still thinking if the teleporter should be here (lower level) or above on the walkway on the upper level. But I think the lower level is the better choice, makes the lower level area more significant.
Shot 2
Red glow is a bit strong indeed.
Shot 4
You might like to check more skyboxes. IIRC the sticky thread in this forum, has some good links for more of them. Obviously if the sky is more or less uniformly colored, that would be kinda boring. Maybe use something with clouds or mountains that will show over the walls.
As an alternative you might want to build a few breaks in your outer walls, like windows or balconies (I'd like the balconies), to let the player look out. This should not lower FPS significantly, and would also break up the long walls in Shot 4 e.g.