So here's the deal: you're the alien, naturally, and you have to shoot down a load of meteorites and asteroids whilst rotating around a planet that you're trying to save. The more space rock you destroy, the higher your score.
Despite the simple premise, the game promises to keep you playing until your battery has run dry. If the graphics don't get your attention (they probably will), you'll still be busy beating your score or playing multiplayer mode, so if you tend to procrastinate a lot then watch out.
Instead of rambling on about how cool the game looks, I'll just let you download it and check it out for yourself. It requires Android 2.3 or later, and you can get it now for free from the Play Store.