Very beautiful game! The atmosphere is quite beautiful and the game play is simple yet intuitive and engaging. As specified the game does lag a little bit which could potentially mess up the immersion into the game. Might I suggest trying to load your assets from a server interchangeably? It turns out with flash games mp3 and image files can be the largest assets that contribute to lag, especially animations.
Also, the music although beautiful is a tiny bit loud. turn down the volume a bit (or give the option for the player to tune it to their liking) and I think that this game would be great!
Other than that this game is going in my favorites list!