Canabalt is an elegant and addictive side-scrolling game with an extremely simple interface and premise. You play a suit-wearing office-worker who is running and jumping across a series of rooftops and other structures, while you see the city behind you in the midst of some sort of mysterious giant-robot assault.
The interface is very straightforward: you run left to right automatically, steadily picking up speed (if you avoid obstacles), and you tap the screen to jump, with the longer you press, the farther you jump. That's it. But as you run, you have to contend with all sorts of hazards--always random, so you can't learn them through trial and error--from boxes and office chairs that slow you down to explosions, glass windows, and buildings that crumble beneath you. Games are short and when you (inevitably) die, whether from a mistimed jump or an unfortunate collision, you see the distance that you covered in meters, and you can tap to try again.
Combined with its foreboding techno soundtrack (indeed headphone-worthy, as the game suggests) and stylish lo-fi visuals, Canabalt's simplicity makes repeat play irresistible and satisfying. The game's only serious flaw is its price. The quality of this game is indisputable, but given its narrow scope and the similarly high quality of other lower-priced iPhone and iPod Touch games, Canabalt isn't a particularly good value. (Fortunately, you can try the Flash version for free online to judge the game for yourself before buying.)