In this game you are in a tank and the screen shows your view of the landscape outside. You gain points by shooting enemy tanks, supertanks, missiles and saucers. Experts gain scores of around 150,000 points at this game. To get a high score you have to destroy twenty tanks as quickly as possible. After this the supertanks, missiles and saucers appear. These are worth far more points than the ordinary tanks.(The number of tanks you have to destroy before the supertanks appear varies on different machines.) Try to approach an enemy tank from the side or the back, so it cannot shoot at you. Then, when you get close, turn to face it, line it up in your sights and fire before it turns to shoot at you. If you miss or are too slow, quickly escape by moving out of the enemy's line of fire. You can then move around the enemy and came in from another side. When a supertank appears, try to destroy it. Then wait safely behind an obstacle for a missile or flying saucer. The cubes are useful objects to hide behind as you can fire over them without exposing yourself to danger. The missiles will fly straight at you, but they are difficult to hit, so do not shoot at them until they are quite close. The saucers are much easier to hit, but do not chase them as you will be open to attack from enemy tanks. This information refers to ______.