It´s incredible how adicting and frustrating this game is. Probably with random seed level design like an infinite mode would really fit in and get some replayability (and a record ranking table). Besides it´s dificulty which isn´t really a problem if it had a better dificulty curve. I think this game needs some better kinestetic, make the act of pressing the correct letter something more pleasant for the players and pressing the incorrect one more stressful. This game shine at it´s best if you decide to make scalated frustration like "getting over it".