SOS

SOS is a fixed screen arcade shoot 'em up. The player takes control of an air plane which can move left and right along the bottom of the screen. The aim of the game is to shoot down the enemy planes that fly in straight lines vertically from the top to the bottom. Any collision with one of them will lead to a life lost. The plane shoots one bullet at a time which has to be off the screen before another one can be fired. Shooting while moving the plane leads to a diagonal movement of the bullet. The game goes on until the player has lost all lives or when 100 enemy planes has made it to the bottom of the screen. At times an SOS signal is heard and the letters are written on either the left or right side of the screen. If the player manages to reach the edge of the screen in time the number of passed enemies will be reduced by nine.