Orro2008 the alien fighter

Game purpose: Kill all aliens before they get you. Win with fastest time and with highest score possible. Instructions: To start , first you must select difficulty level (between 1 - 9) Tap anywhere on the blue area of screen to shoot at alien Tap on bottom green area to move player ship. You start with 3 lives. Each time you are hit you loose one life. Hitting alien gives 10 points. Hitting a ghost alien gives you another life. Hitting ufo gives 100 points. Best score is measured by both best time and highest points. Each level has its own best.