Jean-Clement Sorret was the digital colorist for the film, and is one of the few instances where a colorist received a spot in the opening credits. The film contains many coloring effects and “density shifts” of lighting to reflect the moods of the characters. For example, when Hayley gets angry the colors would be edited to be of lower frequency. One effect used which, as far as the director is aware of, had not been done in cinema before, was to brighten the lighting in filming and recorrect everything down in post-production. This allowed for facial details to be visible even while having a darkened atmosphere

Patrick Wilson briefly passed out due to overexertion during filming of the intense surgery scene.

Due to the controversial nature of the film, the budget was kept under a million dollars so the studio wouldn’t ask to change anything.

During the film’s premiere at Sundance, the Dolby surround system failed. David Slade held up the premiere until they could get it fixed.

According to actress Ellen Page, the iconic red hooded shirt used in the movie and on the posters was, in fact, orange. The color was changed in post-production.

Both cast and crew members have denied that the costume choices for the character of Hayley were intended as a reference to the children’s story Little Red Riding Hood.

Only nine minutes of music is used throughout the movie. Most of the soundtrack is made up of ambient sounds and heavy breathing.

When they were filming the scene where Hayley implies that everything Jeff thinks he knows about her is a lie, producers asked if they could include a line where she states that she was actually 18 years old rather than 14. Ellen Page was adamantly against the suggestion because she thought it undermined the premise of the film.

Despite the intense emotional and physical content of most rest of the movie, Ellen Page said that one of the hardest scenes to shoot by far was the scene at Nighthawks, where for take after take she had to eat more tiramisu than she could ever want.

Sandra Oh agreed to her small part in this film mainly because of her previous working relationship with Ellen Page, a fellow Canadian.