Nice game overall, it felt really fresh right off the bat, but it got repetitive after I figured out how to do really well - using knights, and nothing else. I beat hard, and am playing panic mode now, and though the greater difficulty is welcome, it still feels repetitive. Nonetheless, well done for a flash game!
Good game and very innovative. Unfortunately repeating levels to get full stars can become a bit of a chore. Managed to get through normal, got stuck half-way through hard. I do enjoy having to be more tactical in hard mode. However I won't purchase stars, I feel it's a cheap way out of a game if I have to pay to be able to beat it (I want to beat it of my own accord). It does seem like you've made it almost impossible to do without doing so though. Someone earlier said to do the first freeplay level for easy stars. I don't know which one the "first" is, but find them all incredibly difficult and feel like these all need a purchase to be able to stand a chance.
Very original way of interacting within the game, the gameplay itself is fun and challenging, very well done.