The object of the game is to rescue your friends in the world of Sway by swinging your way through levels by collecting stars and keys to unlock additional Sway friends that you can also use. Each character seems to have some distinct characteristics (speed, strength, arm length) which keep things interesting.
The controls are unique and do require some training. When you first start the game, you are going to fall... a lot. Don't worry, that's normal (I think). There's a bit of a pace that you need to capture to properly sway. Illusion Labs does a good job with this instructional video which teaches you the basics.
I think it's not an exaggeration to say the entire game revolves around the controls. The levels are essentially progressively harder obstacle courses for you to navigate. While this is likely also true for most any platformer, this fact was somehow more apparent in Sway. What this means is that if you love the controls, then you'll love this game. And that's not a necessarily a bad thing, since there are many who do love them.
The 15 included levels, however, can go by rather quickly, and I do wish the gameplay were better "paced". There is no penalty for falling/dying. You simply restart at your last checkpoint, having lost nothing except a little time. While this may mean you get a bronze instead of gold medal, all unlockables can be achieved through brute repetition rather than (necessarily) improving your skills. This also means you can make it through the earlier levels well before your skills might be "ready" for the later levels.
Still, there's a lot to love about Sway. The graphics, music and style are wonderful. The entire package is just very well put together, and you will find yourself replaying earlier levels once you get the hang of the controls. Each level has Bronze, Silver, and Gold achievements based on how many stars can be collected within a certain amount of time. The unlockable characters also add a reason to keep playing.
This gameplay video shows one of the middle levels and one of the later levels:
Despite our criticisms about gameplay pacing, the overall Sway experience is probably one of the most polished and uniquely "iPhone" experiences available in the App Store, and it would be hard not to recommend on that basis alone.
App Store Link: Sway, $4.99