The visuals are beautiful. Coming from thatgamecompany, the people who gave us Flow and Flower, this is unsurprising. Movement is fluid, and the controls work exactly as you would expect.
The multiplayer aspect is the most interesting part, though. As you play you will be paired up with someone. You won't know their PSN ID until after you finish, you can't talk to them or send them messages. Your only form of communication is a visual and audible blip. Somehow, though, this works. As people disconnect, you'll lose them from your game and connect to someone else.
Once, toward the end of the game, I had been playing with the same person for about 45 minutes when they suddenly dropped. For just a few seconds, I was distraught. In that short time, with only bell sounds and flashy lights to communicate, I had gotten attached to this companion. It was only when I realized and examined this emotion that I shook it, because it was immediately replaced by amazement at what this simple little game had done.
Play it. That's all I can say. If you have a PS3, you need to play this.