the idea is very innovating, a game like Mario vs Donkey Kong but a city builder is a neat idea, but the execution of the proof of concept is very weird. The fact that the monkeys stop out of nowhere and you need to press rescue is frustrating because it interrupts the activity i was doing. And the camera controls I would prefer them with a drag with the mouse, but using keys is your vision for the game so i can take it. 

Oh, and, on Godot there is a section of Tooltip, for this genre of games that is needed, so, you could add a tooltip description to every thing on the build section.

Overall, a neat concept.