Done about 80 levels perfectly now. They are reasonable difficult but nothing you get stuck on for too long. 100 levels might seem like a lot but you 'cut' thru them pretty quick. There is a fair bit of variety that gets unlocked with each box that keeps it fresh. I really enjoy the use of multitouch and it actually makes some of the levels quite tricky when it comes down to timing. Highly recommend this game at the bargain price of 99c.