I think this is my favorite entry in this series. I think it mostly works because of how different it is. I'm not that much of a guy who's into puzzle games, but this was a nice exception. It mostly works because there are just so many different ways to play. I can't believe there are only sixteen levels! There's so much variety you think there would be more.
I love how the simple graphics work so well. I know I've said it a million times, but simpliticty in something can work great. You just have a nice sense of knowing what you are doing. Even the music is calm and peaceful. It's also easy to pause.