The folks over at Touch Arcade are doing a terrific job of keeping up with all the good-looking games on the App Store (and even some not-so-good-looking ones) but for my money, this one falls solidly into the first category.
Rock'n'Roll is an accelerometer-based puzzle/platforming game (ported from other mobile platforms). As you can see in the video above, it plays like a much more colorful version of the already-fun Spinner, as you rotate the iPhone to control the little circle and get him to fall down in the right place. There are power-ups and items to collect as you explore the little mazes, and though there's no sound in the video, we're told the game will have a "traditional Americana" rock soundtrack, which sounds like fun.
A few people have mentioned motion sickness, and while that's a possibility, my guess is that it's more from the video itself -- playing Spinner has kind of the same effect, but when it's you controlling the spinning and the image is confined to the iPhone's screen, it's not so bad. At any rate, we'll find out soon whether the game is as fun as it looks -- it's due for a release later this month.