This was pretty fun to play, and the duck, of course, is a big plus.
Some notes: It felt like the notes' placements weren't entirely synced with the music, such that the quacking wasn't on the rhythm entirely (though that might just be an FPS problem on my side). And, as others have mentioned, a penalty for quacking with no note is a must for a rhythm sort of game like this one.
Overall, it was cool. Well done!