KAMI is one of the best puzzle games I've played in a while. The concept is simple and the gameplay is challenging, which is right up my street. Add all that to the beautiful aesthetics and soundtrack, and you have yourself a near perfect game. Although the game is a little short, I have gotten 9 hours of fun (and, sometimes, frustration... and then relief upon finding the solution) out of KAMI so far, and I definitely see myself returning to it at some point. Well worth the price.
My only real gripe is that the second set of the premium puzzles were much unlike the others, as instead of simple colours, the folded paper had harsh black and white patterns, which really hurt my eyes and made it difficult to focus on the screen, which meant I had to keep coming back to them later. I understand that the patterns were used to add to the difficulty, but it wasn't for me.
Other than that though, the game is perfect (in my opinion, of course), and the level of difficulty is just about right. You can always aim for "OK" scores rather than "perfect" if the challenge is a bit much on some of the puzzles, but personally I love the challenge of solving the puzzle in the absolute minimum number of moves. I definitely recommend KAMI and I look forward to trying other games created by State of Play.