Well, I gave it a look and ran around it for a while earlier today, and overall, you have some good stuff going on here.
I can't really comment too much on the texturing--it's not really my strength, and I don't make textures myself, but I didn't see any problems.
Suggestions/Observations:
1. I *think* I like the sky in the screenies (the blue one) better, simply because it serves to add a bit more contrast into the level. Right now, the vast majority of the level feels sorta brownish/goldish/earth tones, and since the sky is now at a similar place on the color wheel, it seems to me like the level has a "sameness" throughout that could maybe use a bit more contrast in there, whether that's a sky that contrasts with the overall color scheme of the level, or some texturing that stands out a bit more here or there, or more contrast in light brightness/color? Dunno...
2. I'm not finding many movement options in here via slope-jumping or other trickiness. Seems like it wouldn't be too hard to add some here and there--you already have the sloping trims on the stairs, so maybe a hop from there to a projecting bit of wall or trim or a light or something and on up for a shortcut? A bit of rubble near MH that if you do it *just* right will allow you to hop out the top? A bit of projecting trim that allows you to hop across from one upper part of an atrium to another without having to go down and back up? That sort of thing.
3. There's a weird thin light triangle near HB on the floor...
4. I see a few walls here and there that are completely black--not sure how much you're hurting on light count, but it seems odd.
5. The RG pedistal feels awkward. I'd lower it to 16 so it doesn't act as an obstacle.
6. Are you aware that you can customize jumppad color via key/value "_color" "r g b" on the func_static?
Hope this helps.