Dreams Eternal is an FPS game that focuses on a strong story line and puzzle solving. It is set in the dream world. The very short summary of the story is that a scientific experiment went wrong and everybody is stuck in the dream world. You have to end this experiment by hopping from dream to dream. In every dream you have to find clues to try to find out how the experiment can be aborted.
Crystal Core is a FPS quest-based game written with Crystal Space and Crystal Entity Layer. The game is based on a science fiction story. The player and his or her companions crash on an alien planet where they discover that the original intelligent inhabitants are now extinct due to an invasion of semi- primitive aliens from a distant planet. Your goal is either to destroy all aliens or escape the planet alive. To accomplish these goals you have to use alien technology and try to interface it with the broken ship that you arrived with.