Alien invaders from nearby Alpha Centauri star system come to invade Earth. It is up to you to defend it. Fight in space and on Earth. Play levels 1 through 15 on easy, medium, and expert modes. High scores feature allows you to keep track of your past scores for each skill level.
Download from Google Play
https://play.google.com/store/apps/details?id=com.ericsweeten.invadersfromalphacentauri
Eric Sweeten's Blog 