Goofs

(at around 19 mins) When the coroner, Dr. Adam Heffner, is talking to Hoffman and Agent Dan Erickson and Agent Lindsey Perez, he says that the knife used to remove the jigsaw piece from Eddie had a partially serrated edge. Dr. Heffner then claims that same knife was used to cut the jigsaw piece from Seth Baxter. However, in Saw V (2008) the knife used to remove the jigsaw piece from Seth Baxter is a non-serrated scalpel, not the "knife with a partially-serrated edge" that Dr. Heffner claims was used.

(at around 7 mins) When Hoffman raises the lid of the "Glass Coffin", the blood remains on the lid in a fixed pattern, showing it is dry, even though it was only spurted on to it seconds before.

(at around 6 mins) When Hoffman's "Glass Coffin" ejects after escaping the "Crushing Room", his face is visible. However, in the flashback footage from Saw V (2008), Agent Strahm's blood spatters further across the panel, hiding Hoffman completely from view.

(at around 16 mins) When Simone is in the hospital, and Detective Hoffman visits her, there is a hand on her shoulder in the close-up view to calm her down after Hoffman asks her if she learned anything from her test. However, when the camera zooms out a few seconds later, the nurse is just then going up toward her, to put her hand on Simone's shoulder.

(at around 1h 24 mins) For Detective Mark Hoffman to get his other hand out of the chain, he would have to use the crushed hand, yet if his hand bones were even mildly broken, he couldn't have used them.

When John Kramer is ill and going through chemotherapy, he has a small, thin beard on his chin. Chemotherapy kills rapidly dividing cells, such as cancer cells, hair cells and fingernails. It would be impossible to grow facial hair when going through this therapy.

(at around 32 mins) When William escapes the "Oxygen Crusher" he gets a key to one of the straps that are stuck to his limbs, which he immediately uses to take the strap off his hand and then he throws it away, yet in the next shot of him, he is taking the strap off and then throwing it away to look at what it says underneath.

Actually, what William throws away is not the strap, but the metal device containing the explosive intended to amputate his limb.

(at around 56 mins) During the "Steam Maze", the trajectory of the trap (a spear that will pierce Debbie's head if she does not locate the key in time) is completely off. When it fires, it is shown entering her neck, but a couple seconds later it is seen sticking out of her skull above her left eye. It should either have gone through her neck and out the back, or sticking out the back of her head instead.

(at around 12 mins) When Detective Mark Hoffman is brought to the scene of the first crime, he looks down at Eddie, who is seen breathing, even though he is already dead.

When William saves Addy from hanging, in the last shot as he is walking away a hand pats her on the right shoulder.