Revealing mistake: It's obviously a fake head when the doctor is drilling the skull as indicated by the increased amount of hair as compared to facial shots of Jigsaw. (01:02:20)
Continuity mistake: Kerry's hand is severely burned from the acid, but in all following scenes her hand shows no burns. (00:16:00)
Suggested correction: They do show burns throughout the rest of the scene.
Continuity mistake: Amanda's hair is in a lose ponytail when she sees Jigsaw holding Lynn's hand. A large part of her hair is hanging down the right side of her face and in her eye. She storms out of the room and now all of a sudden her hair is all pulled back in a tight ponytail and no hair is hanging down or behind her ear, it's all back in the ponytail (instant cut, no time for her to re-do her hair).
Continuity mistake: When the tape player says "The key is among your son's possessions" Jeff is standing in front of the opening between the bars leading down to the ladder, and he takes a few steps towards the incinerator (his left). The screen cuts back to Jeff and you can see in the lower left-hand corner of the screen that Jeff is still standing in front of that opening between the bars. (00:56:10)
Continuity mistake: There is a closeup shot of Matthew's foot right before he starts to smash it with the broken piece of the toilet bowl lid. He's placing the flashlight on the floor next to his foot and you can see that the sock is back on his foot, even though he took it off previously (right before he first attempted to saw through his leg). (00:03:20)
Continuity mistake: There is a far-away shot when the first pig comes out. You can see Jeff standing on the platform holding his left hand to his face, there's an instant cut to a close-up of Jeff, but now his right hand is held up to his face. (00:58:45)
Continuity mistake: In the close-up shot of Lynn removing the piece of Jigsaw's skull you can see that she's holding the instrument in her left hand (look at the position of her fingers), but in the farther away shots she has it in her right hand. (further evidenced by later in the scene where you see a close-up and she's still holding the instrument in the left hand and a knife is in her right). (01:04:30)
Continuity mistake: When Jeff is monologuing about how "Everyday for 3 years I wanted to kill him" there is a tear that appears in his right eye and starts to run down his cheek. The shot cuts away for a second, then back to Jeff and there is no tear, not even a wet tear trail.
Continuity mistake: There's a shot of the right foot when "The Rack" starts twisting it. There is a blood trail that runs off between his first 2 toes, and a lesser one that runs off between his 2nd and 3rd toes. The screen cuts to a close-up of the foot and there's only the blood trail that runs off between the first 2 toes.
Continuity mistake: The guy that is in chains stands up, looks around and takes in what he sees. There's a shot of him from the front and his hands are semi-clenched in FRONT of him, around waist level. The shot cuts to behind him and his hands are a good 4 or 5 inches OUTSIDE of his hips. (00:06:35)
Other mistake: After Jeff gets the key from the Rack trap room, the shotgun fires and hits the judge. He is standing with the shotgun to his right, yet he is hit on the left side of his face. There is also an inconsistency with the timing. The gun fires, then the actor turns to reveal the wound on the left side of his face. It's easier (but in no way required) to see the glaring mistake with slow motion.
Continuity mistake: When Kerry is looking in the closet, she is right by the door. Camera changes has she has jumped about two feet back instantly. (00:12:30)
Visible crew/equipment: Just before Amanda shoots Lynn, a mini microphone can be seen on Amanda's neck. It is only visible for a few seconds then vanishes, so look quickly.
Revealing mistake: Look at Matthews' toes as soon as he's done breaking his ankle, it's obvious that it's a fake foot. If you shine a flashlight through your toes, or fingers, it will shine most brightly through the edges of them because in the middle there's a bone to block the passage of light. The light shines right through Matthews' toes, and it's a solid color, obvious that there's nothing inside to block the passage of light. While he did break several bones in his foot to escape, it is unlikely that he took time to break his toes as there is no reason to, the shackle will slide off unbroken toes as well as broken ones. Also, even if he did break his toes, the broken pieces would still be in his foot and still block the light. It's a fake foot. (00:04:15)
Continuity mistake: The blood streaks on the chained man's chest continually changes from almost covering his chest, to less noticeable. They probably tried to give the appearance of his continual bleeding, but the shots didn't make it into the movie in sequence. (00:06:25)
Continuity mistake: The knot and string position on the tape player is different during the close up of it on "The Rack" guy's chest than it is during the far away shots.
Revealing mistake: During the "pig vat" sequence, as the pigs are being dropped into the grinder, in some of the shots from underneath the blades, you can see that the pigs are not falling directly into the blades, but rather, onto a sheet of glass right on top of them. (Look for the pigs to reflect in this glass.) (00:56:00)
Revealing mistake: When Jigsaw is coughing up blood, the tube pumping the blood is visible. Look near his thigh. You can even see some red liquid oozing up. (Only visible in widescreen.) (00:38:20)
Continuity mistake: When Jeff sees the doll on the wrecked trike you can see that the doll's hand is on the trike tire, but in later shots (of the doll from the waist up) the wheel and tire and nowhere to be seen.
Continuity mistake: When Jeff reaches up and plays with his daughter's hair some of her hair falls over/in front of her stuffed animal. The next shot of her (instant cuts) and her hair is back behind the animal. (00:31:00)
