Plot hole: An order is given for the body of John Kramer to be exhumed. Surely the police would have noticed someone had dug the grave up in the last few hours (days at a push) as Logan had to get Munsen's body into John's casket.
Revealing mistake: When Mitch's tape plays, if you look closely you can see the tape is not actually moving inside the recorder. (00:45:15)
Revealing mistake: At the beginning when the coroner cuts the bucket off the body, the metal is red hot and her pinky touches it. Not only does it not burn the glove but it doesn't burn her.
Continuity mistake: When Logan is shown the message found on the second victim, the string in the evidence bag attached to the note changes between the close up and the far shot. (00:28:30)
Continuity mistake: When Carly dies we see her fall down onto the right side of her face. Camera cuts to a close up of the blood pouring out of her ears and neck, and she is lay on the floor on her left side with her right side of her face upwards. (00:20:30)
Continuity mistake: The amount of blood on the memory card Logan finds changes between shots. (00:12:30)
Continuity mistake: At the start Edgar smashes his car up and kicks his window out and jumps out leaving a bit of glass in the window frame. However after the camera changes, the 2 bits of glass have disappeared. (00:01:05)
Audio problem: When Logan explains how Edgar killed Logan's wife, the camera is an over the shoulder shot looking at the cop. Logan's mouth isn't moving. (01:18:05)
Factual error: The depiction of lasers is completely off in the movie. While surgical laser is indeed a real thing, such a highly concentrated beam with enormous cutting power seen in the film would take industrial size instruments and an extremely high power supply. Also, a laser beam simply doesn't look that way. Those scenes are way off into science fiction for an otherwise raw and realistic-looking thriller.
Continuity mistake: As Anna and Mitch get trapped in the silo, various sharp and pointy tools begin to fall on them (a pitchfork, circular saw blades, nails, etc.), but when Ryan finally pulls the lever and the silo door bursts open, they all disappear. Only the wheat and the trapped duo can be seen "flowing" out.
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.
Suggested correction: The metal is not red hot, it was cut by a laser that gives off a small amount of smoke. Nothing says the metal is hot. So no burn is reasonable.
Ssiscool ★
Your correction suggestion completely contradicts how laser-cutters work. The metal would definitely be hot if cut with a laser cutter. That's how laser cutters work - they essentially melt the material they're pointed at in a very controlled fashion, and they do indeed get quite hot.
TedStixon
Smoke doesn't make the metal glow red, that would be heat. Also for the laser to cut through thr metal it needs to heat it up.
brianjr0412