you fight against the intruders .you are a space ship in the game. Once it starts, you will be located in the airspace where numerous enemies move towards you. You can use （→）and(←) key to turn in clockwise direction and turn in counter clockwise direction to define the direction. meanwhile, you can use spacebar key to shoot and use (↑) key to speed up. During the game, equipments can be collected to arm your own ship after shooting down the intruders. Make use of the keys to win the game. More shootings, higher score. Are you ready? Play now.