YMMV / Serenity

  • Cult Classic: The movie didn't perform very well financially, but it is almost universally loved among the show's original fans.
  • Crosses the Line Twice:
    • Included in the blooper reel is an extra take of the shot in which Mal orders his crew to mask their ship as a Reaver's. The original scene is very nearly a Kick the Dog scene, but the moment Mal's improvised orders change from the script is the moment that he takes the line and guts it with a screwdriver. Seen here.
      Mal: Put Book front and center; he's our friend, we should honor him. Kaylee, find that kid who's taking a dirt-nap with baby Jesus—we need a hood ornament. Jayne! Try not to steal too much of their shit!
    • More canonically, after Mr Universe's Heroic Sacrifice, we see him lying dead... in the arms of his own love doll. With his final message recorded in it.
  • Ear Worm: The Fruity Oaty Bars commercial might only be designed to trigger Manchurian Agents, but it'll worm its way into anyone's brain.
  • Fanon Discontinuity: Believe it or not, some fans of Firefly refuse to acknowledge this film's existence, primarily because they refuse to accept Wash and Book's deaths.
  • Hell Is That Noise: Reaver ships constantly broadcast the sound of dozens (possibly hundreds) of people screaming.
  • Hilarious in Hindsight: Jayne snaps at River, uttering "I'll show her good and all, I got man parts" in "Trash". Fast forward to the Curb-Stomp Battle of Maidenhead, and...
  • Memetic Mutation: "Ceiling River is Watching You Fornicate."
  • Moral Event Horizon: The Operative's destruction/massacre of anywhere/anyone Serenity might go to for help.
  • Retroactive Recognition: Solomon Northup is the Operative.
  • Some Anvils Need to Be Dropped; Belief in something greater than yourself, be it in God, or just in a moral cause (such as justice for the settlers of Miranda), is essential if you want to live and not merely survive.
  • They Changed It, Now It Sucks: Some fans of Firefly were not pleased that the "space western" elements from the TV show were dropped in favor of a more traditional sci-fi feel. This is ignoring the fact that many entire episodes of Firefly are largely sci-fi and had little "western" to themnote  and the entire intro sequence of the movie is as pure "space western" as you could get.
  • Uncanny Valley: This is where the lovedoll designers of the future are situated.
  • The Woobie: Both River and Simon.