After doing the zombie typing minigame the game stopped accepting inputs, specifically after i closed the animation window, using latest version of firefox.
Also, the piano minigame speeds up each time you try it, eventually making it unplayable. It was also way to hard to begin with, why do the numbers/letters not correlate to any sort of physical position? It makes the game more confusing than it has to. It was also quite the jump in difficulty already from wave one to two. More numbers than can be comfortably typed from one position on the keyboard was already a jump, why then also add letters?