I found the game a challenge to control, particularly as more obstacles were added in the later stages of the game. But I'm up for a good challenge, and for me, Air Penguin's controls never became too frustrating to use. That's a fine line, though, particularly in a casual game like Air Penguin. I'd encourage people to take the out for a test spin first to see how they feel about the tilt controls. It puts limits on the number of stages you can complete, but it will give you a good feel for the game before you commit to the paid version.

(One other note about the controls--in the kind of extended gaming sessions I do for testing, I found all that flicking and tilting to be a little tough on the ol' wrist. That likely won't be a problem for users playing Air Penguin in its intended manner--short bursts when you have a spare minute or two. But if you get easily addicted to games--and Air Penguin is --you could find yourself nursing the iOS equivalent of tennis elbow.)

In addition to Story mode, there's also a Survival mode requiring you to keep your penguin aloft and out of the water for as long as possible. I didn't find the Survival mode to be as compelling as gameplay in Story mode, but I appreciate that it's there to keep things fresh.

There are a lot of nice, little touches in Air Penguin--you can make out the outlines of shipwrecks in the water below, and occasionally, a school of fish will swim by. The background is cute, and sound effects--like the chomping noises those sharks make when they try to devour your penguin--are particularly well done.

Tempting though it may be to compare and contrast Angry Birds and Air Penguin, I'm going to resist. The former may rule the App Store roost, but the latter is a in its own right.