- Ability over Appearance: The filmmakers originally planned for the cast to be both male and female, but Neil Marshall's business partner realised that horror films rarely have all-female casts.
- Acting for Two:
- A prop example. They only had one cabin, so they had to use camera tricks and prop switching to make it look like there were two.
- Leslie Simpson played two Crawlers and got killed on screen twice.
- California Doubling: Set in America (aside from the beginning of the movie), filmed in England and Scotland.
- Cameo Prop: Sarah finds a wolf's head, which is a prop from Dog Soldiers.
- Completely Different Title: The Danish title for the movie is Descent Into Hell.
- Enforced Method Acting:
- Intended, at least. Neil Marshall attempted this by not letting the main cast see the crawlers until they were revealed on camera. However, it backfired when they got such a fright they all ran away for real, out of the shot and across the set. Even long after the first encounter the actresses hated being around the crawlers in costume.
- Even after the reveal, he kept the actresses separate from them most of the time to keep up the feeling of animosity.
- Shauna Macdonald is claustrophobic anyway, making the scenes where Sarah is trapped in a tunnel very easy (or not) for her.
- Fake American: Natalie Mendoza is British-Australian, playing the American girl Juno.
- Fake Nationality: Sam, who is Dutch, is played by Myanna Buring, who is Swedish.
- Looping Lines: A good chunk of the dialogue had to be dubbed in, because the sets were polystyrene and sure didn't sound like a cave or rock while they were walking or moving around on it.
- No Stunt Double: Shauna Macdonald, Natalie Mendoza and Alex Reid did the entire white water rafting sequence on their own without any stunt doubles or special effects.
- Production Nickname: The jokey production name given during filming was Chicks with Picks.
- Production Posse: Leslie Simpson played some of the Crawlers, and has also starred in Neil Marshall's Dog Soldiers.
- Too Soon: The 2005 Underground bombings in London threatened to delay the film's British release, for fear that this trope would keep people away from a film about death below ground. Eventually the film was released on schedule, but posters of a lone woman trapped and screaming in the dark were replaced by new ones of all six women standing united against it.
Trivia / The Descent