Space Outlaw is one of the games I am most proud of. I had two goals for the game. First, I wanted to make a game that was not just colored boxes like many past games. The second thing was to learn about Google Play services and integrate them in a meaningful way. I think I did that and learned a lot from doing it.
In Space Outlaw, you fly forward when pressing the screen. However, you are constantly moving left and right, so the challenge is to pass all the obstacles trying to kill you.
You only get one life, so you need to take time and learn the pattern in the beginning. Then, as you get better, you can get a bigger score multiplier by flying close to obstacles and longer without stopping. Because of the Google Play integration, you can also see your friends score and try to beat them.