Not a bad marble shooter, till you reach the point where you literally can't get on without spending actual cash. Which isn't that far in, actually. You soon find it almost impossible to get three keys on each level without buying bonuses(you usually need only 1 to move on, but 3 for the full awards and kudos), but early in the second stage you hit a wall where you can't even get one without a bonus. Which is when I uninstalled it.