Cripes, this is a tough game! The first 10 levels are easy, and then the difficulty goes through the roof. The puzzles are well-made. Nearly all the ones I saw after level 11 had one very obvious set of moves that would leave you one move short, and the player has to discover a not-so-obvious move somewhere within that sequence. In some cases, you have one move too many. Therefore, it's important to discover where you need to conserve and where you need to waste.
The "undo" button is very much appreciated, as this is the sort of game where dismantling your sequence can be a better way to learn that to completely reset, even if that can be useful too.
The tutorial tells you all you need know, but it might be better to make it interactive. Learn by doing.
Also, the control can be a little off. There were plenty of times I struggled to grab a tile with the mouse. Nothing too bad, though. Perhaps I was rushing.
Otherwise, you've got a mute button, home, level select, decent music, and the sound effect is satisfying. The graphics are simple as they should be, but smooth. Very polished game!