This game is polished, unique, and almost bug free. There is a huge bug with the pause button — if you pause and come back sometimes the game will freeze, causing you to lose your progress, which is frustrating. Sometimes the game will lag for no reason— as if the character is underwater.
Otherwise, the game is brutally difficult. It’s difficulty makes progress deliciously rewarding and there’s a somewhat consistent sense of progress, to keep you coming back. (That progress stops after a while though.) Regardless, the rush you feel after every run, success or fail, surpasses the frustration of the ridiculous learning curve. I do not recommend the game for anyone without a keen sense of rhythm; the rhythm is obviously a core part of the gameplay, and having not yet mastered keeping rhythm will make an already hardcore game a lot harder. You have been warned. However, if you have or are playing an instrument, like I am, then it’s a phenomenal game.