Wish I saw more of the theme in use, I liked that the harvesters were moving trucks but that was about the extent of it, which was a shame considering another tower was also a type of truck.
Though I know it's not easy to do in a short timeframe, I would have liked for the difficulty to be more balanced and for the attacking to have more impact. I can see though that you put a lot of effort into the setup of the game and so I hope you continue to work on it.