Music, perfect but a little loud. :)

But else, the concept seems cool, but some kind of end would be cool. Because with an ending the game feels more finished. For example that you have 2 Minutes to break as many windows as possible or that it becomes increasingly difficult to hit the windows and if your hit rate goes below e.g. 40% the game is over and you get some kind of highsscore (which could be just the time you survived). 

(I played until the music looped, so maybe there is an ending afterwards. In that case, just ignore the previous paragraph)