* AlternateCharacterInterpretation: It's entirely possible that Grace already knew about [[spoiler: her husband's death in the war]] but was in denial about it, and the knowledge that [[spoiler: he wouldn't be coming home]] is what drove her mad in the first place.
* CrowningMusicOfAwesome: The entire soundtrack.
* EsotericHappyEnding: Or a BittersweetEnding, or a DownerEnding, depending on your views. [[spoiler:Grace killed her children, and they are all presumably forced to dwell in the house forever, separated from their husband/father and with no indication that there's a higher power looking after them. However, they have resolved most of their internal strife, the children are no longer harmed by the light, and Mrs Mills' general demeanour suggests that being dead isn't really all that bad. Grace even manages a small, grateful smile when she offers to get her a cup of tea]].
* HarsherInHindsight: [[spoiler:The twice-repeated "Stop breathing!" takes on a tragic new meaning after the final twist.]]
* JerkassWoobie:
** Grace is rather nasty but she's just had to live through World War II, her husband has been away fighting and she's tasked with taking care of two children who can't be anywhere that isn't in the dark.
** Anne is a bratty little thing as well but it's hard not to feel some pity for her when she's frequently at odds with Grace. Especially the "you're not my daughter!" scene - where Anne is very good at looking like a kicked puppy.
* OneSceneWonder: The old woman that Anne has brief visions of. She only properly appears in one scene towards the end [[spoiler: being revealed as a medium]] but she's one of the most memorable parts of the movie.
* RetroactiveRecognition: Recognise the voice of Victor's mother in the scene towards the end? It's [[Series/GameOfThrones Catelyn Stark]].
* RewatchBonus:
** If you watch the film again after learning that [[spoiler:Grace and her children were DeadAllAlong, you'll notice how a lot of the things they do are common with what people usually associate ghosts with (erratically moving things, wearing creepy clothing, talking/making noises in acoustic hallways/rooms, not leaving their home etc.)]]
** Charles's reaction when he first sees Grace. [[spoiler: Well, how would you react if you discovered your wife and children were also dead]]?
** There's a point in the movie where Grace kisses her children while they're asleep. Anne in particular looks extremely pale and lifeless. [[spoiler: It's {{Foreshadowing}} that she's a ghost]].
** When Grace first picks up the rifle, she's seen looking at it curiously - as if she remembers something. [[spoiler: The same rifle she killed herself with]].
** Grace frequently complaining about migraines [[spoiler: since she shot herself in the head]].
** It's said that the servants abandoned the house without notice and the postman didn't collect a letter last week. [[spoiler: The servants left when their mistress and her children died, and the postman didn't go to the house as it was unoccupied]].
* SciFiGhetto: A horror film that broke out of the ghetto. It was advertised as a ghost story and the trailers played up the horror elements. It ended up becoming Spain's highest grossing film for years, and Nicole Kidman even got a Golden Globe nomination for it.
* {{Squick}}: The "book of the dead" Grace finds, filled with photographs of corpses posed for portraits. What's amazing is that the film ''downplays'' this [[http://en.wikipedia.org/wiki/Post-mortem_photography very real practice]] -- In the film, all of the corpses are posed either alone or with others of their kind, with their eyes closed as if to be asleep. In real life, most such photographs involved living family members -- and their eyes were [[UncannyValley very much open]].
* TheWoobie:
** Nicholas is the youngest child in the house, and his only companions are the servants, his erratic mother and his bullying older sister. Of course that's not even getting into his photosensitive condition.
** Lydia was left mute by something that traumatised her, and she looks so sad in every scene. [[spoiler: Discovering she was DeadAllAlong too]].