Continuity mistake: The amount of blood on Bobby's teeth constantly changes. During the tooth room. (01:02:00)
Deliberate mistake: If you look at the IP address of the junkyard, it is listed as: 634.634.99.234.88. An IP never goes over 255. (01:00:10)
Continuity mistake: During the public saw trap, when Brad is clipped by the saw, you see blood on the edge of it. However, when the angle of the camera changes, the saw is clean. When the angle switches again, there is blood on the saw. (00:05:55)
Continuity mistake: It is visible that Dr Gordon's handwriting when he writes " I know who you are", is different from the handwriting in Hoffman's letter. (01:19:40)
Continuity mistake: When Bobby is swinging from the cage near the start, the way he is holding onto the cage changes instantly. (00:31:40)
Revealing mistake: Most of the blood seen in this film is too light to be considered real human blood. In the public trap it is practically pink. The reason for this is the 3D effect. When watched in 3D, it looks more like normal blood. But in normal viewing, it does look too light. (00:06:00)
Visible crew/equipment: When Bobby grabs the key for Cale's noose. There is a shadow on the door of a boom mic. (00:53:50)
Continuity mistake: When on the chat show, the mug belonging to the host is constantly moving. Check the handle. (00:13:30)
Continuity mistake: Brad gets blood all up his face when he is hit by the saw. When Ryan and Brad decided to let Dina die, the blood has gone from Brads face. (00:06:40)
Continuity mistake: Gibbs smashes the glass at the junkyard with a shotgun. The smashed glass changes between shots. (01:26:20)
Continuity mistake: In the public trap we see Ryan's overalls are done up. However, in one shot they are undone, then done up again. (00:05:50)
Continuity mistake: When Gibson asks Jill if she knows who the man in the picture is, he is holding the picture in his left hand. When the camera cuts it is now in his right hand. He's also reaching between different bars. (00:48:40)
Continuity mistake: When Jill is in the police interview room, the key round her neck keeps moving position, as does the mug by her. (00:10:30)
Continuity mistake: When Jill is running into the evidence room, the dead cop has got his trouser leg up revealing some skin. When Hoffman is locking Jill into the chair, look out the door and the trouser leg is down. (01:12:10 - 01:15:10)
Continuity mistake: Hoffman shoots the cop guarding Jill through the eye and some brain matter appears on the prison bars. Camera changes and the brain matter has disappeared. (01:11:20)
Continuity mistake: When Jill notices the trike there is a shadow by the bike. When the angle changes, the shadow has gone. (00:16:40)
Continuity mistake: When Bobby is pulling teeth, he gets blood all down his shirt in one shot. Camera does an instant cut and the blood has disappeared. (00:59:20)
Revealing mistake: When Bobby's wife is dragged to her knees by the chain, you can make out the shape of her knee pads under her trousers. (00:41:10)
Continuity mistake: Just before Nina dies, Bobby covers her mouth with his right hand, and holds the side of her face with his left. When he does, his hands are apart. Camera changes and his hands are now touching. (00:41:00)
Continuity mistake: The amount of nut shells on the bar when Bobby gets his idea changes between shots. (00:32:40)
Answer: Dr. Gordon from the 1st movie, and Ryan and Brad from the trap in the beginning of this movie.
derrick g