From Wikipedia: Knight Force is a computer game developed by Titus Software in 1989 for the Amstrad CPC. The player is a champion who must travel to five different time zones in order to battle an evil magician who has captured a princess. The player must fight a variety of enemies in order to retrieve the correct amulet for each time zone. The player must also kill a number of clones of the magician in order to slay the real conjurer and rescue the princess. Source: Wikipedia, "Knight Force," available under the CC-BY-SA License.