This game is great!
I really don't care for puzzle games at all, (I like to kick ass and take names) but this game is just fantastic. It held my attention the entire time I was playing. It really works your brain, despite the simple concept, and the fact that there are multiple solutions to each puzzle takes out some of the stress. I actually managed to get all of the way through medium, although I did get stuck on Level 8 for quite some time. That really should have been a level later in the game. It killed me on hard mode, too. I was doin' just fine until I ran into Level 8. Anyway, apart from some small errors (according to some other reviews the mute button doesn't work [turn off your speakers, genius], and Level 8 is too early in the game, [should have been 17-20 somewhere]) this game is unbelivably good and I think anyone looking for some brain stimulation should play.