Revealing: After Dr. Lawrence cuts off his leg and is crawling towards the gun, if you look at his dismembered leg, you can make out the shape of his foot hidden beneath his ripped up slacks.

Continuity: When Adam pounds on Zep with the toilet seat, he grabs his shoulder in pain. In the first shot of him holding his shoulder, his hand is soaked in blood. In the second shot, however, his hand is much cleaner.

Continuity: When Larry is desperately trying to reach for the cell phone, he uses the box that it came in. When that doesn't work he throws it off to the side (his left) but when we see it again the box is back where it originally was (on his right).

Continuity: When Alison gets the gun from Zep and aims it at him, the gun is in her left hand. In the next shot it's in her right hand, and then it moves back to her left hand again. This is not an artifact of changing camera angles, you can clearly see the different hands holding the gun.

Revealing: When Adam is searching Zep for the key to the chain once he has found the tape recorder watch Zep's tummy - he's breathing.

Visible crew/equipment: After the first call when Dr Gordon gets on the cell phone, a boom mike shadow is visible on the bathroom door.

Continuity: When Larry looks at the picture with Zep at the window, from one angle the picture is all crumpled but in the first person view, it's smooth. This changes several times.

Factual error: The Swedish subtitlers made Amanda's situation even more tragic, incorrectly translating her dead cellmate as her dead soulmate.

Continuity: When Dr Gordon begins to saw his foot off, the blood seen covering his neck and top disappear in subsequent shots.

Revealing: In Adam's flat just as he starts beating Jigsaw's doll (Billy) up, you can see that he's not actually hitting the proper puppet, but a cheap replica. You can tell by the red lines on it's face, and there is no red marks where it's mouth is.

Continuity: When Dr. Lawrence opened his envelope he got a key in it. When he tried it on the lock on his chain and it failed to open, Adam then asks to try it. Right when Adam asks for it, he puts his tape and envelope down separate, but when reaches for his tape again, it has ended up inside the envelope.

Continuity: When Larry takes the box out of the wall, it turns itself around from when he's holding it, to when it's on the floor (keep an eye on the box's padlock).

Factual error: Dr. Gordon is seen in a close-up to be sawing through his leg, some inches above the ankle joint and the shackle around it. Considering the long bones of the leg (fibula and tibia) are very tough in a young man, it would take a long time to saw through by hand, during which Dr Gordon should have passed out from pain-induced hyperventilation then died from shock.

Visible crew/equipment: In the scene when Adam walks around his apartment with his camera (because the lights were out) the filmmakers put lights in the set so the actors wouldn't walk into walls, and also letting the audience see what's actually happening. In the movie, though, there are supposed to be no lights on at all. However, just before Adam opens the closet door with Jigsaw in it, you can see the reflection of one of the set's lights on the top of Adam's camera.

Continuity: When Dr Gordon is going crazy, he throws the box to his right, but in the next shot it's on the left, then on the right again.

Continuity: Adam's hacksaw blade snaps almost as soon as he gets it. However, later on (just after he gets electrocuted) we see it lying beside him with the blade in one piece.

Continuity: When Dr Lawrance first notices the clock on the wall and tells Adam about it, the time on the clock is around 4 o'clock, but in a later scene after he is told he must "kill Adam by 6 o' clock," the time on the clock is much earlier, around 11-12 o'clock. That much time wouldn't have passed between seeing the clock and finding the tapes.

Revealing: When Larry notices the clock on the wall, he puts his hand on a pipe. Watch the pipe, it bends in and foams out when he takes his hand off it, revealing it to be made of foam.

Continuity: When Adam throws the picture that he found in Lawrence's wallet to him, the picture lands next to the rectangular piece of tile that Lawrence uses in the immediate next shot to bring the picture closer to him. The tile moves from in front of him (given it's proximity to the photo) to right beside his right arm/hand. It "moved" about two feet.

Continuity: When Adam retrieves the bag with the saws from the toilet, he places it on his right side. At one point you can see that there is nothing on his left side, but the next shot shows Adam grabbing the bag from his left side and tossing it into the tub.