Raiding faces until the break of dawn.
Face Raiders, formerly known as Face Ace, is going to be pre-installed on 3DS when it comes out in March. What I played is extremely similar to the tech demo at E3 2010, but now it's a full-fledged game.
First, you take a picture of yourself, a friend, or something else. Then, the game maps it onto an enemy ship, and you fight off the onslaught of faces while trying to save other faces of people who previously played the game. It's ridiculously charming, especially because the faces are altered to make them look even goofier at times.
It also has a bit of augmented reality in it as the world around you serves as the background, and the enemies destroy parts of it, sending some of it at you.
There's a score element to it as well, and multiple levels. Face Raiders might be simple, but it shows off a lot of cool things that the 3DS can do.