- Contrary to the marketing's claim that the film was shot in one uninterrupted take, the entire movie was actually shot to mimic one continuous real-time take, with no cuts from start to finish, as a result the time span of the film's plot is exactly 86 minutes. It was shot in roughly 10 minute segments then carefully edited to hide the cuts. This was confirmed in an interview by Elizabeth Olsen and the directors.
- Due to the unique nature of the film's presentation as a single take, the production crew ran into several technical issues while filming, mainly surrounding lighting issues and mobility around the house. Since filming was carried out in 12-15 minute takes, there were several occurrences where entire sequences had to be thrown out and re-done repeatedly due to lighting problems or missed cues.
- Elizabeth Olsen is in every single scene of the film and the story is told from her point of view, the film never shifts to another character's perspective.
- Director Chris Kentis describes the film as an "experimental film".
- Olsen stated during an interview that she suffered from nightmares during filming simply because she would think of frightening things throughout the day.
- This is a remake of the Uruguayan horror thriller film La casa muda (2010) which employed the same "continuous" take technique.
- The film's plot begins roughly around 5:52 PM and ends at 7:18 PM.
The world premiere of the film was at the 2011 Sundance Film Festival, as part of the "Park City at Midnight" program; Kentis, Lau, and Olsen also appeared. It was released theatrically in the United States on March 9, 2012.