In The Crypts of Plumbous, the player has to fight alien ships who are trying to raid underground Nuclear waste storage for some unknown reason and unleash it on the planet.
Journey to the Planets is a space adventure puzzle game for Atari 8-bit computers. In the game the player is lost on an alien planet, and must avoid enemies and solve puzzles in order to get back home.
Being King Arthur's favorite in succeeding him on the throne of Camelot, your king sends you on a quest to retrieve the Scroll of Truth in order to prove yourself worthy.