As tower defence games go, I found it quite relaxing. Made it to wave 20-something but got distracted with a conversation and died. The camera movement was way too fast for me - mouse and keyboard on a laptop. Combined with the camera shake, I never even got to see the enemies!
As has been mentioned by others, spheres of influence/can't build here representation would be good. I'd also like to click on the minimap and move my camera to that location.
Not the strongest connection to the theme, but not the worst by a long way.