Cool App!
A great spin off of a classic game. The controls take some getting used to, unless you have played a lot of similar games. There are four of them: spin left, spin right, fuel, and fire. You have to rescue astronauts as they fall of asteroids before they drift off the screen or get killed by aliens, which is an added to challenge to simply destroying aliens. The user interface is pretty unique also, and fits well with the retro feel of the app.