It looks promising, but like PohyCZ said, some notes are offbeat (the notes in the slow part are to early). You may also need to add an audio offset parameter to let each player configure it as the average sound card add a lot of latency. And it also need more feedbacks when pressing a key, validating or fail a note like flashing lights or something. It's disturbing not being able to clearly see what you're doing.
I'd love to see your game in a more advanced stage. :)

Yikes...this game is hard! Lol.

My fingers are kinda twitchy and so I'll hit keys on accident. But I guess with practice you'd get used to it.

Good game!

Nice little game. :)

fun, simple to understand and easy to play :D I love it, would like the same things PohyCZ requested as well, but still really nice, would love it see more :P 4/5

The notes aren't in sync with music. But i liked it, even thought i was failing. :D Greate potential! Add editor, statistics, more songs and maybe multiplayer?