Gravity Defender is simple action game requiring a little skill and a little luck. You are a ship in trying to survive in an endless sea of enemy ships. There is hope though. There are different power ups such as Increasing in size, guns, a bomb, and a shield. Try to play for as long as you can. It gets more difficult as the levels increase. Every time you increase to a new level, you gain some health back. If you run out of health, the game is over. Here is the key:P = Power Up - makes your guy bigger and strongerS = Shield - protects you from the enemies and the boss for only a limited timeB = Bomb - blows up all the enemies on the screen; does not affect the bossG = Gun - shoots any enemy on the screen including the boss for only a limited timeIt was made to be completely free. There are no ads, in-app purchasing, etc. I made it for my son for fun and thought someone else might think it was fun too. So, if you have any suggestions, please just let me know.