While I'd grown accustomed to Jetpack Joyride's original title, Machine Gun Jetpack, the Apple overlords probably thought the game deserved a slightly friendlier title. It could also have to do with the fact that the game's star, Barry Steakfries, can purchase many different backpacks. It doesn't have to be a machine gun strapped to his back.
It could also be a jetpack that runs on rainbows.
Either way, while you wait for GameRevolution's official review, you should just go ahead and download Jetpack Joyride. It's got a ton of unlockable content, arcade-y replay value, and a jetpack that runs on bullets, the makers of Fruit Ninja seem to know what gamers want on the go. Priced at only $0.99, you can't really go wrong.