Beautiful
Great concept, easy fun, and good design. Everything looks very professional and the music is relaxing. The biggest grip I have with the game is that I don't feel like I'm playing a music game. "WFT??" you'll all say, "the points are moving according to the rythm!" Yes they sure are, but MY actions are not following the rythm, so in my head, my movements are not adding to the experience, which might have been better.
It also get's a bit repetitive after a while and would last longer with more tracks, features and ways of playing. To be perfectly honest, I was a bit surprised to see this on the number one spot. A part of me likes the fact that it is, because it shows NG is maturing a bit, but the other part of me feels like this was a very well designed demo of what to come next, and not a true competitor for first place. Acctually, I think that might be a good way of describing it, seeing as there is bound to be a sequel/expansion.
I'm all about good ideas, and this game has a really good idea. Now all it needs is time. Time for polishing, extending and elaborating on ideas. Once it is, I'm sure it will be an easy game to sell. You should think about making one for the iPhone app store that opens next month, you'll be a millionaire ;)