Amazing. It's very difficult to come up with something that's actually negative about this game! Past personal preferences and the rare bug, the game itself has little to no issues. The option of playing on 'Zen mode' were you can just go down an endless hill with endless lives and incredible music is a great addition to the main game that I regularly use! Overall, its the best mobile app I've found in a long time, and I strongly suggest installing it even if it's just to try it out!