Trivia: Writer Dan O'Bannon's idea for Alien evolved from a comedy B movie he'd written a few years earlier called Dark Star which featured an alien that was a beach ball. O'Bannon said that he was unhappy with the silly alien in "Dark Star" and deliberately steered away from potentially comic elements while writing "Alien."
Trivia: For the wide shots where we see Kane and Co. walking around outside the Nostromo, Ridley Scott used children (two of which were his own) in special child sized space suits so the sets would appear bigger in comparison to the people on screen. He used the same tactic again when they discover the fossilised space jockey on the alien ship.
Trivia: A few scenes that showcased the crew's casual attitude toward sex and bisexuality were planned at various points, including: a sex scene between Ripley and Dallas after Kane's death; a "post-coital" moment between Dallas and Parker; and a moment in which Ripley speaks intimately with Lambert and finds it odd that Ash hasn't tried to sleep with either of them. This last scene was the only one of these filmed and it, too, was cut in order to make the crew relationships more ambiguous.