* 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.
* RewatchBonus:
** If you watch the film again after learning that [[spoiler:Grace and her children were DeadAllAlong, you'll notice how alot 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]]?
* {{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: Grace, Nicholas and Lydia.