While this map is very well made and looks brilliant, I've found a few gameplay flaws:

High mobility classes, such as scout, soldier and demoman have a massive advantage over the other classes. Maybe add more "fake roofs"

Snipers on the BLU team have massive sightlines to pick off RED players. Possibly add more cover.

The hills that the cart moves down should probably be rolling points due to how steep they are.

There is a slight problem with the hill after the first point that makes the cart unable to push for a second. I noticed a slight variation in the gradient of the slope. Possibly the problem?

And last but not least, and I know this will sound odd, but switching the positions of BLU and RED would make the map play a lot better. The way it is now, BLU has a massive height advantage after the first point, making it very hard for RED to defend. If BLU pushed the cart UP the hill, the map would balance out more.

Well, make of these points what you will. That's just what I found while playing. Besides that, the map is brilliant and very fun to play on. Good luck with your future mapping! :3

-Fredurgonnadie