Continuity mistake: At the beginning of the movie when Jamie leaves his father, his stepmom Ella follows him and his father's head remains in an upright position. However at the end of the movie when Jamie has a flashback of everything that happened, it shows Ella was using his father as a puppet. In the flashback sequence when she lets go of his father to follow Jamie, his father's head automatically drops on his chest and does not remain upright like it did earlier.SAZOO1975
Trivia: The making of the film was a troubling experience for writer Leigh Whannell and director James Wan. The story was created at the last minute for a pitch to studio executives who wanted to hear something from the "'Saw' guys" (even though they had no concrete ideas at the time), but after the project was greenlit, Whannell found it difficult to write as he was not fully passionate about the project and didn't expect them to give the go-ahead to make it. Upon completing the first draft, he then spent well over a year doing copious re-writes over and over to appease various increasingly harsh notes the studio gave him, including notes he felt made no sense. (Ex. The executives in charge kept pushing him to create "rules" to make the story more grounded and realistic even though it was a story about an abstract ghostly curse.) Eventually, an uncredited script-doctor was brought in to re-write the film, and Whannell has stated that the finished film is a mish-mash of his ideas and the script-doctor's. The shoot ended up being hectic and troubling for director Wan, and a great deal of content was cut from the film, including a good deal of the twist finale and a good deal of the backstory related to the various villains. Whannell has said that although the project was a failure in his eyes, he would do it all over again because it taught him many valuable lessons about filmmaking.