Ok, I have allot for you. First, the lighting needs work. Looks like your ambient light is too high. This makes the unlit areas (outdoors) look horrible.
This roof needs a texture other than solid black. And you might want to have a different texture for that smoke pipe, but that's not too important.
I like this idea, but your floor is
way too thick. You also might want to use a different texture (maybe planks?) and have the hole in the floor line up with the planks (so it doesn't look like a cleanly cut hole).
This door is a bit too big, both horizontally and vertically. You should make it so the player can just make it under the top of the door at the peak of a jump.
I really like the broken chairs in this room, but you need to watch your texture alignment.
Here is that solid black texture again. I would avoid using it. It looks like there is no roof.
The textures need to be rotated.
Here is a perfect example of the lighting issue. It looks unlit, and the texture doesn't look good on those stairs. Change the lighting, and chances are, the stairs will look better.
The shadow is off by a little bit. You need to move the light entity to the center of the light brush (not vertically though).
This looks like you just slapped that together in 5 minutes. Get fancy with it. Make it look really nice.
Make this hole line up with the bricks. Just like the floor above, only on a wall. This looks too clean cut.
A bunch on this one. Are these supposed to be train tracks? If so, why do they end at ladders at both ends? These are also
really thick tracks. They need to be maybe an quarter the thickness. The ladders need to be narrower and need the textures rotated (this applies to
all of you ladders). Also, that wall texture does not look really good tiled. Different lighting will help, but I'm not sure if that would be enough.
Again with the black texture.
This just looks a little odd. Especially the one support. You need more of a variety of bricks/concrete in the out door areas.
This is some really thick glass. Looks like at least 2x the thickness of bullet proof glass.
Lastly, the horrific black texture yet again. This one looks like the lights are floating and there is no roof. Blends in almost perfectly with the sky.
Over all, I like the general design and creativity of the map. However, the out door area is very empty so you need to clutter that up a bit. That along with a few small tweaks, and this map could look and play really good.
Oh, and don't put the textures in "pball\textures" put them in a folder called "pball\textures\tlc2dm" or something similar.