Very good puzzle mechanic. After a short while I was able to think through the puzzles and complete them with relative ease.
I would suggest the addition of buttons to either send me to the level select screen, or to allow me to replay the level I just completed. Just for the sake of convenience really.
So far levels 1-9 completed perfectly, however completing 10 in any less than 8 moves proves to be a challenge. For the record, knowing what the perfect score is would be nice.
