To fire at someone behind you, select either Viper missiles (5) or Bion Fury Missiles (6). Press V twice, so that the game switches from "chase" to "outside" view. Turn the viewpoint around by using [Inser or [Delete] so you can see behind yourself. If there are enemies behind you, fire your missiles. They will fly towards the enemies, even though you are not facing them. Note: This will not work with Dead-On Missiles, because they are not homing missiles.