Its a really clever game with good concept. My only critic will be about the validation of a level. The fact that you require a certain amount of moves to validate a level is not really good. In puzzle games, the player should be able to do as maximum moves has he wants to complete it. It will be better with a star system : You can let the player continue even with 50 moves but you get 0 stars. If you do the level with the moves required, you get 3 stars etc.