Move your mouse to move the fighter, Use spacebar to shoot the lasers, hit the monsters. When you hit the monsters, they explode. If they reach the end of the screen, that's okay. Other fighter planes will take them down. If the monsters reach you, then it's game over. Press Green Flag to restart. P.S. If the explosion touches you, of course you'll be blown into oblivion, then it's game over too. Update: I added a score system!
