Deliberate mistake: Per his autopsy in Saw IV, John Kramer was 52 years old at the time of his death, and this film takes place between Saw and Saw II. Tobin Bell was around 80 years old at the time of making this film, and thus looks far too old to convincingly play someone in their early 50s. Amanda Young also looks a lot older in this film compared to other entries in the franchise that are chronologically later.
Deliberate mistake: When they're watching the footage of the tsunami hitting Cannon Beach, Sabrina turns the TV off as the shot pulls backwards. Suddenly, the glare on the TV appears out of nowhere.