Alien: Earth adds surprisingly good TV dimension to veteran sci-fi

After fifty years of books, games and movies, what more could the Aliens franchise deliver? The description "genre-defying" gets thrown around a lot these days - it is a convenient sticking plaster for any film or series that hasn't quite figured out what it wants to be. That said, it is an apt term for the Alien franchise. Ridley Scott's 1979 movie Alien, in which Ellen Ripley (Sigourney Weaver) is part of a crew trapped on a spaceship with a salivating, scorpion-like "xenomorph", had such blood-curdling visuals that it made an indelible impact on both science fiction and horror films. But while the deadly parasite and its psychosexual torment were ever present, subsequent instalments tried their hand at being everything from a blockbuster to a prison flick to a philosophical drama.