This is very well made. I do like the idea of a civilization simulator evolving into tower defense. The combination feels refreshing. I particularly like the fact that there s a progression to dynamically choose what building you need to build to meet the optimal resource need.
That said, I think there could be a few minor improvements. I believe it would be very helpful to have a UI element that shows the current production and consumption rate for each resources. And it would be helpful to include an undo button because I have mistakenly placed candy refuges and waste many blocks since they can't be destroyed. But overall, gameplay-wise it's very well made for such a short development time. Great work.