The window moves around when controlling the character on firefox, Google chrome works fine though. Pretty neat concept trying to catch the platforms before they disappear but it looks like the game just kinda hangs until you reach the very bottom.
The game stops responding after falling about 9-10 (I wasn't keeping track) screens worth of levels but the music still keeps going. Not sure if there's supposed to be a game over screen there or another level or whatever. This happens on google chrome but I haven't tried it on other browsers.