Meh. Needs work.
The music is super awesome, seriously. But for the love of god, PLEASE make it numpad-friendly, or else do SOMETHING so that the up-down combined notes aren't finger-destroying. I dig the 'chords' thing, but up/down just does not work. DOES NOT.
It took me a bit to figure out what to do when two notes came from the left and right at the same time--a note in the instructions about that would be nice.
The note timing seems a little off, too, like you have to key in a bit early. Also, dropping the volume when a note is missed is diabolical and counterproductive--you are making it HARDER to recover, which is precisely the way to get people to hate your game.
It also merits mention that the color coding with regards to direction is nearly worthless, since the notes come in from so far away it's easy to tell which direction they are. What you should instead consider is using color to denote their place in the music with regard to the beats--this is one of the reason Dance Dance Revolution remains superior to its knockoffs; you can see whether something is on the beat or off the beat without waiting until it's too late to adjust your input.
Despite these things, I had fun playing it, but I had absolutely no desire to continue fighting against the mechanics to keep playing when I lost on the third song. You've got a good idea going, though, and I hope to see an improvement on the execution in the future.