The film was shot digitally, but director and editor Mike Flanagan, in order to add a retro feel to the film, added elements in post-production to give the appearance of a movie shot on film. Those include the 'sigarette burns', marks that appear every 20 minutes or so in the upper right corner of the frame, which were used to signal a change of reels for film projected.
Scenes that appear in the trailer but are missing from the final cut are: Jenny choking her father to death, a scene of Doug Jones dressed as a doctor turning around slowly, and the highly advertised scene of Doris in the doorway giggling.
"Ouija" is a trademark of Hasbro, Inc. but is often used as a generic term for any talking board. There are different theories for where the name came from. Two very popular theories are that the board itself told its creator what to name it, and the creator came up with the name after combining the French and German words for "yes" - oui and ja.
Director Flanagan says he wanted to create the thriller as if it were shot in 1971. Some techniques included antique lenses, scene fades, and camera zooms instead of steadicams. Other simulated techniques: dust on the negative, subtle warping of the audio track, reel jumps and split-diopter (where both the foreground and background are in focus).
With the release of this film, it marks the first Hasbro film, as well as the first Platinum Dunes film, to be well received by critics and get a certified fresh rating on Rotten Tomatoes. All the previously released films such as the Transformers films, G.I. Joe films, Battleship (2012), Ouija (2014), and Jem and the Holograms (2015) received a rotten rating.
Along with the missing footage from the trailers, Chad Heffelfinger and Nina Mansker's scenes as ghouls were cut from the film despite still being listed in the credits, while the majority of Chelsea Gonzalez's scenes as Gloria were removed as well.
Mike Flanagan in an interview revealed that the original cut was 130 minutes with 40 minutes removed from the final cut. Doug Jones's scenes as the devil's doctor trimmed or removed entirely, Chelsea Gonzales's scenes as Gloria were cut as well, and Kate Siegel had at least 2 more scenes which include another visit to the Zanders' and the choking scene with her father.
The trivia items below may give away important plot points.
Contrary to expectations, Doris isn't necessarily possessed in the film, at least not in the traditional sense. After she complains of a sharp pain in her neck, the spirits bend her backwards and enter her body, using it as a conduit. She was killed after that scene as they broke her back. Throughout the rest of the film it is just her possessed corpse housing the spirits.
After completing the first cut of the movie, director Mike Flanagan and producer Jason Blum felt that the ending wasn't strong enough and the last scene with Lin Shaye confusing. Production was resumed for two days in Los Angeles in order to shoot additional material: Elizabeth Reaser, Annalise Basso and Lulu Wilson were called back to shoot a longer and more emotional version of Alice's demise and the doctor's scenes in the asylum (with newly cast John Prosky). The last scene with Lin Shaye was moved after the credits because people thought it was a connection to the "Insidious" franchise.