Not bad for a 2nd map,
but it feels very empty ... and I can't see a lot of tactical stuff going on really;
those underground passages for example - always put in by novice mappers as it seems.
They're not a good idea IMO,
you don't have any choice when you've gone into them.
Try to create maps that keep the player free to move around as he chooses and pick alternative routes on the spur of the moment as often as possible.
That way you won't get people (who know the map really well) always fragging you just when you come out from those tunnels for example.

Also - I found a small glitch (which I seem to remember from Cube was sometimes only visible for players using linux nvidia drivers) in that sand-pit (the one you get to e.g. by that gray ramp) - at the bottom of this pit some cubes are shimmering weirdly ...

Items are a bit sparse too, I can't even remember seeing any health-packs lying around.

Keep at it, try improving on this map too - and I guess your next map will be all the better because of it ;)

Sorry for suggesting the idea, but what else could we put in the middle? Nothing? Then it would have been a 'real' empty map...Health packs...where are they? Ammo...hmm...
And we can do something about the open spaces in one of the bases, for example, set up boxes like in ac_aim? It would be interesting trying to round around it...maybe
The texture at the bottom should be rounded off for a bit of a realistic look...

Maybe make a 'on air' route...jokes...but you can do it ; )
Also, some originality with the textures, not too flashy, but not the 'usual' texture of deserts?
<><><>Pretty simple. Get tons of sarcasm here. Then, consider about the sarcasm, use one of it and make better maps. Thats how it is. Theres certainly better mappers than me because they spend more time on their maps.