Galaxy Express is a fun little puzzle game that's similar to Chu Chu Rocket or Chuck the Ball. There's a cute metagame story in this app with some well-written dialogue, but the core game has you pushing a little astronaut around a starfield using some arrows that you place out on the game screen. Put arrows in the right places, hit go, and the little astronaut will follow your rules exactly, hopefully leading him to make his delivery on the destination planet.
It's simple stuff, and the difficulty doesn't ramp up too quickly, though by the end of the game's 120 puzzles there are a few mind-benders to beat. There are some good social features as well, including the option to either see any of your solutions that you've done, share them with friends, or even check out what other people have done. There's Game Center integration in the game now, and the graphics aren't really animated, but they look good on a high resolution display anyway.
Galaxy Express is currently available at just 99 cents for a universal app, or there's a lite version you can pick up for free. "Galaxy EX," as it's called under the icon on the phone, is a well-made little puzzle game that's easy going enough for almost everyone to enjoy.