Very simple but interesting game. you have to kill Alien, Ghost, Spaceships.
In this game, there are many types of enemies. You have to kill them. For killing any enemy you will score one point. Each enemy will spawn a bullet when it dies. Collect these bullets quickly as they will disappear soon. Ammo is limited so use carefully. If you miss you will lose a bullet. The boss will come once you have killed enough enemies. You have to hit him several times to take him down. Fortunately the boss sometimes drops bullets, grab them fast. There is a guardian angel. He will drop lives. Collect them quickly, you have only Five of them.