Use Roll and Yaw on your phone to control the defending ship and stop the alien invasion. Fire with HUD control on the right [circle], switch directions with double arrow above it, advance with the arrow below it. Stop with the HUD on control on the left [square], move up with the one above, move down with the one below. The aliens and starship images came from gameartpartners and the sound effects from zapsplat. Shake it to get the option to play without advertisements in between games.