33 minutes and 20 seconds later:
Do you really think this map was worth it? I will let you know if you were right.
[EDIT]
Its obvious that you have either never been inside a cave before or, you are not shooting for realism. Something that the HL2 engine can deliver BTW.
1] discounting the lighting, which I assume will be augmented to give a cave/underground feel, I cannot add anything to the comments about lights until I see a more advance compile. All the unskinned props are ruining the feel/atmosphere.
2] the wooden planking. Again, it doesn't look realistic. Planks are added to an existing aperture. yours actually inserts itself within the walls in places. Its obvious that you have a considerable amount of overlapped solids present.
3] again the plank pathways. You need some upper support. Ropes, chains or cables. Its not important what but something needs to be holding all that lumber up.
4] the wind? again, not realistic. caves with that much of a breeze needs an outlet. Preferably in the top. a volcanic vent type hole would suit.
5] the planking again. all of them seemed to be made of the same wood, and running the same direction. alter the material and direction a bit.
6] slow the waterfall down a bit or perhaps decrease the volume of water falling over it. a fall of that type would steam up the whole area in fog.
7] rock types, although many caves contain the same materials, many are often wet and dry in places. try to make yours appear so.
8] have a few broken guard rails scattered about. preferably made out of rope or chains/cable
9] light rays from the sun through cracks can increase authenticity and depth.
10] tone down all noises. caves are horribly quiet places. also, sound is swallowed up easily in caves, keep the volume at a level so you cannot hear it all from everywhere.
11] unless this is a new cave, there will always be some material either falling from the ceilings, or building up on the ground. new caves may do this to but the edges will be sharper. older caves have rounded edges.
12] if these opinions do not suit you. ignore them.
There is no history until something happens, then there is.