Deliberate mistake: The coordinates listed for Hobbs' soccer game (34.1381N, 118.3534W) at the beginning are not actually a wooded suburban area with a recreational field, but are in fact the longitude and latitude for the Universal Studios Hollywood theme park in Los Angeles. (00:15:20)
Deliberate mistake: During his autopsy in Saw IV, it is revealed John Kramer was 52 at the time of his death. Kramer's role in this film is the very early stages of his time as Jigsaw, shortly after his cancer diagnosis, which would put him in his early 50's. However, he looks far too old to convincingly be that young (Tobin Bell was in his mid-70's at the time of filming). He even looks older than he did when he was on his deathbed in Saw III.
Deliberate mistake: The front passenger's side mirror [driver's side is on the right] is parallel to the screen/camera yet there is a perfectly clear image of the passenger's face looking into the mirror. (00:00:38)
Deliberate mistake: One of the bodyguard's rifle which is a Sig model SG553 only has a front sight and no rear sight. The rear sight can easily be attached to the Picatinny rail. Such a rifle is only good for up close instinctive shooting, anything at distance is spray and pray. (01:39:00)