So you got around doing the barrier and planning stuff, eh?
EDIT:
I played it for a bit (not for to long, it's time to sleep now
)
It's great, though here are my exclamation marks:
-I noticed at least one place where you used 2 pillars on 1 spot to create sharp edges in your walls, however, since they are at the exact same height, you get some rendering issues. It can be revolved by moving 1 of the objects just a pixel downwards.
-You can use texture variation to make the map have unique locations, right now everything looks a bit like each other.
-Some of the planning you did had too sharp turns (at one place, the AI would literally make 90 degree turns) Try to make the pathing more arching, and a bit more wide, for both realism and gameplay purposes.
Work on the background a bit more, since some of the sniping spots are close to the boundaries of this map, you can clearly see that the background scenery is very small. My suggestion, make some hills in the background, place some more of the "billboard" objects in the far back etc. etc.
-Try to use custom lighting, even if you'd only change the ambient light #1 to a very light orange, the map would look loads better.
It's really good and original enough from the stock level, great job!
and i uploaded it to GT a few days ago, but it magically vanished. I think the jawas must have taken it... so I uploaded on filefront today and here we have it.