Your game has a huge potential and I could even pay for a more developed version but as it is right now it's not special. The graphics and sounds are perfect and the concept excellent but the survival part is not quite interesting and too hard past level X (it has to be re-evaluated). As for the economical aspect of the game, you've seen everything past level 1, which is regrettable.
It would be truly amazing if there was a possibility to choose a game mode (plus a peaceful mode) and the possibility to build a geater town and castle with a much more complex economy. As previously said, I think the basics of this game could be the fondations of something much greater.
Great work. I'd love to see more of this.