Wow. This was actually really cool! I think it'd benefit from being scored for more than just gold efficiency, because it allowed for some /really/ obnoxious solutions, but I was actually disappointed to hit the final puzzle--I really felt the last one was where the game encouraged you to prove you understood what was going on instead of just making an adhoc solution.
Straight up, I wish it was longer. This was a lot of fun, and a great way to spend the evening.