If you're one of the many people who always loved the Super Monkey Ball games on consoles, but never could really get in to the iPhone and iPad iterations because of control issues (I'm definitely one of those people), Aerox [$1.99] by Synoptical Studios is worth checking out. Aerox features extremely clean looking graphics, almost as if the game itself was designed as some part of a Aperture Science training program. This graphical style is paired with soothing music which creates an oddly relaxing experience-- A phrase I never really thought I'd use to describe a ball rolling puzzle game.
Much like Super Monkey Ball, the object of Aerox is to roll your ball to the end of each level. In between the beginning and the pillar of light you must reach are all kinds of crazy obstacles ranging from simple ramps, moving platforms, and narrow platforms. It doesn't take long for the difficulty of the game to ramp up and throw other physics-based obstacles at you. For instance, you'll need to bump in to tall skinny blocks to get them to fall over to make a bridge to cross, other times there will be objects you need to move around to pass, or even move out of the way so a ramp can drop down to climb up.
The ball is controlled by tilting, and tilting your device back and forth controls rolling while tilting right or left controls the camera. For additional precision, you can touch and hold the screen and the camera will lock behind your ball at which point tilting right or left causes you to roll that direction. It's a pretty decent setup, although I have found myself rolling out of control by tilting too much and having the camera skew to an unexpected angle. A sensitivity slider in the options would likely solve this problem, which the developer has mentioned is coming in an update in the Aerox thread on our forums.
Aerox utilizes the graphical power of the iPhone 3GS, 3rd generation iPod touch, and iPhone 4 to do realtime reflections on the ball along with some fancy shadow generation not available on other devices. Currently the game runs at the typical 480x320 iOS game resolution, but in the not too distant future is getting updated with complete Retina Display support along with universal iPad compatibility.
With 30 levels to go through, online leader boards (although they haven't been working for me), and updates on the horizon to make the game take advantage of the increased resolution of iPad and iPhone 4, there's a lot to like about Aerox. The game isn't perfect, as I'd love to see some mid-level checkpoints added, but people on our forums are enjoying it, and it's easy to get behind any game with developers actively participating in the forums with plans to implement user suggestions in future updates.