Good map in terms of gameplay, but the lack textures really detract.

Consider looking through the textures pane (F2) and picking out ones that have normal mapping. Some good examples of normal mapping are Melt4 (everything) and the textures on the last page of the texture book.

yeah i concur, the lack of details is the main issue, but that can be fixed.
The main geometry is pretty well, and i like the new tunnel.
I remember, a couple of months ago i started porting some Halo and Halo 2 maps, but never really finished other than Lockout and Beaver Creek maps, hmm, i dont remember if i published the last beta of lockout with the original textures...
Well anyway, good work and keep it that way.
I would be pleased to assist a co-op edit if you or anyone is interested in Halo maps

Cheers Mate!!