Alrighty, so Child of Eden is a really great game. Short, yes, but I can't help but play the stages over and over again. I haven't even unlocked the different visual and audio modes, or difficulty modes, so I can see myself playing through this quite a bit.
I was quite amazed that for the first time while using my Kinect, I was unaware that I was using the Kinect. I didn't feel like I was experiencing a gimmick or felt that a controller would be a better option. In fact, with a controller the game just ain't the same. It's rather boring with a controller, like I'd prefer to play Rez than CoE if I was without the Kinect.
So yeah, great game. If you have a Kinect pick it up. If the shortness is an issue, wait for a sale price, but really I feel good with my purchase.