Great concept, great visuals, I managed to beat the final level without losing once !
I do have a few suggestions; the sound effects need some work, the loud crashing sound and that beep are destroying my ears even after lowering the sounds by a lot. The game is too easy and strategy is not rewarding enough, it felt like it was mostly about spamming upgrades fast enough most of the time. Also the camera makes it hard to select some buildings when they're surrounded by taller buildings sometimes, and some other times the game would select other buildings through the UI when I tried to upgrade them.
Aside from those points, this is very neat and I'd love to see more of it !