I love rhythm games, and this concept reminds me of the guitar battles in Guitar Hero 2 I believe, where there are powerups and attacks that you can use against your opponent. The main problem with this game, and I know it's difficult to perfect everything in just 48 hours so I don't blame you, is the lagginess of the notes, the slow and messy inputs and responses from the game, and the fact that the notes don't seem to line up with the music. I found it difficult to tell if the notes were under the little boxes at the end to indicate that I should press the notes. This may have been part of the design to make it difficult, but it wasn't as enjoyable as having the notes line up like in other rhythm games. If you continue to work on this game there is a lot of polish that you can put on it, and I think that you could make it more fun to play if you worked on making it more clean and precise for the player :)