The similarity to running games like
Canabalt is obvious at first, but
Jetpack Joyride has its own unique spin. The physics of blasting off in a jetpack are actually modeled pretty well, and you'll find it challenging to time both your drops and your blast-offs. Off the starting line, things are relatively slow, or at least you'll realize how slow they are once you progress further. Barry either runs or flys, and the idea is to rack up more distance each time you play, as measured in meters. Distance isn't everything, though. Coins can be collected throughout the level, and used to buy special upgrades for Barry. These aren't performance upgrades, although there are some so-called "utilities" that can improve your chance for a high score.
The extra dimension to gameplay that keeps you engaged with Jetpack Joyride is missions. You always have a bank of three missions to complete, which can be something as simple as "Collect x coins" or something as obscure as "High-five x scientists." Each time you complete a mission, you earn stars. Earning stars confers rank, and there are many levels you can earn before you "beat" the game. Beyond missions are Achievements, several of which are counter-intuitive, such as Germaphobe that rewards you for flying 2,000 meters without touching any of the objects that are associated with rewards in the game. The missions add a layer, and achievements will keep you playing for a good long while. There's even an achievement for finishing all missions and starting the game over. As a testament to the high replay value of Jetpack Joyride, a recent update added another vehicle and some additional goodies, in case you had actually exhausted everything.