Gravity Guy is a fun game that takes some ideas from the running-game genre and adds some unique features that keep it interesting. The main game mechanic is Gravity Guy's ability to reverse gravity, letting him run upside down on platforms and then switch back when he needs to run on the ground again. The first few levels are pretty easy, but as you get further in the game it will require precise gravity switches as you speed through complex courses. To add even more tension to the action, a security guard chases you the entire time (he has the same gravity-switching abilities as you), waiting for the slightest slip-up so he can blast you.
Gravity Guy's control system involves only one thing: tapping on the screen to switch gravity. But you'll need to be careful because the only time you can switch gravity is when you are running on a platform--not while in midair. This means that if you make a mistake, you're likely done for. Fortunately, unlike other running games, Gravity Guy lets you continue from the last checkpoint, so you'll be able to try complex areas again even if you die several times trying.
Overall, Gravity Guy is a fun diversion, even if it doesn't rank up with the top games of the genre. The unique game mechanic makes for some interesting gameplay, especially at later levels, and you can also play four-player multiplayer, but you all have to play using the iPhone screen--possible, but crowded. Nevertheless, if you like running games and are ready for a unique challenge, check out this game.