Good game! Plays really well, looks really good, the tune is catchy, but not annoying (yet). My only gripe with the game is that it sometimes feels a bit too hard to aim, especially for the smaller ones, but that's maybe part of the difficulty.
Great feedback. The small circles are meant to be challenging, but hopefully not to the point of frustration. The browser version also has some input lag which makes it even harder (the desktop version is much more responsive).