Possibly the wisest investment of 10 dollars this year on Apple's App Store is best spent on a game called Rolando. Rolando is an app in the vein of the popular PSP title, Loco Roco. In Rolando, players will find themselves taking advantage of the accelerometer of the iPhone, tilting the cute Rolandos through physics-based puzzles, platforming, and occassional time-based puzzles. Rolando succeeds largely as a platformer due to its non-intensive playing style, and its carefree atmosphere, especially considering how progressively the difficulty between levels slowly ramps up. I think Rolando can be aptly defined as a game that is 'challengeing, but not difficult', even with regards to casual 'non-gamers'.
As the Rolandos are little balls, the player tilts the iPhone from side to side, rolling the Rolandos closer to reach the end of each obstacle-filled level. Each level has a minimum requirement of Rolandos to reach the end of the level -- although it can at times be easily surpassed, given the amount of Rolandos granted by the beginning of each level.
Where Rolando and Loco Roco differ though is quite a point of contention. In Loco Roco, players are granted the ability to smash their Loco Roco into smaller ones, and in Rolando, each character remains the identical size throughout the entire game. The comparisons between each game are somewhat justified, due to each game has a very similar art style, is accompanied by cute, charming characters, and the user's input to each world, both Rolandoland and the Loco Roco planet is the tilting of gravity.