Too linear
There was only one way to win. I'm sure that everyone here used the 10 stack in order to win, and it seemed as if that was the only way. It lost fun points for that. Another thing I noticed is the load time on the catapult. Maybe it was just me, but the load time seemed to get longer as you upgraded the catapult instead of shorter, as the game claimed. The city building also seemed to have one path to take, and if you faltered from it, you'd find yourself with a game over.
Other than that, it was a new look to the defense games. Although I'm not sure what the point of the map was. I enjoyed it, but gameplay was too linear.