Corrected entry: It would be impossible for Hoffman to pass off Seth's trap as a Jigsaw trap. From what I understand, the only trap that happened before Seth's was Cecil's trap, and there was no tape or puppet at that time to be able to imitate. Unless in later movies we are told that more traps happened between the time of Cecil and Seth's traps, this is a plot hole.
Corrected entry: When the Realtor is getting out of the final room, the door is left open and the FBI agent is talking to her. The nail bombs never go off, although the counter never stopped.
Corrected entry: When Agent Strahm is investigating Hoffman, he pulls up a list of previous Jigsaw victims, which include Dr. Gordon, Zep, and Adam from the bathroom game. These people should not be on the list, since the bathroom was never found before this time. The police can't just write these name on a list with merely assumptions, not to mention the fact there is hardly any evidence which could be a link to being a victim of Jigsaw for these people.
Corrected entry: At the end of the movie when Strahm is chasing Hoffman into a house, Hoffman uses a trapdoor on the 2nd floor to lead into a basement. This proves that Hoffman's personal house is actually the nerve-gas house from Saw 2, only refurbished. This also could mean that the fire that is discussed by the five victims was a fire that cleaned out the Saw 2 house. The eight victims that died in the fire were most likely: Jonas, Xavier, Obi, the prostitute, the man who got his head shot off, the blond girl. The last two bodies found have to have been Adam and Gordon's bodies. This means that the fire was set to get rid of the corpses and then Hoffman bought the home and refurbished it to live in.
Corrected entry: After Ashley is decapitated in the collar trap, we see her body later on from the view of the hidden cameras. But by the time we see her corpse, the nail bombs have already gone off and should have caused some damage to it or the room, yet neither is visible or present.
Corrected entry: In the electricity trap, after a brief close up, it snaps to a view of the whole room, you can see the boom mic lifting up and actually see outside of the set.
Corrected entry: There is no way that the grated doors in the second part of the sewer tests would have protected their occupants from a nail-bomb explosion that was powerful enough to pulverize Charles's body. The nails and debris would have been propelled through the doors and fatally impaled whoever was inside.
Corrected entry: When the 5 start the first part of their game (the neck tie trap), they start going for the keys with around 10 minutes on the clock. Yet by the time of the decapitation and leaving the room, the timer is at around 12 minutes.
Corrected entry: After they leave the bath tub room and the door is closed the bombs go off. However, when the 2 of them were in the room the video says that the room will be electrified when time runs out.
Corrected entry: In the first trap of the movie, Seth is in the pendulum trap. We find out that Hoffman put this trap together before he ever met John Kramer. However, on the tv, it is John Kramer's voice talking to Seth, describing the trap he is in. (Also, it is Kramer's puppet that is used in the video.).
Corrected entry: When Hoffman visits Strahm in the hospital the boom mike moves into the picture.
Corrected entry: This movie shows Hoffman helping Jigsaw in the very first game of the very first movie (the obese man who cuts himself.) Which would make Hoffman's game against Seth (the ex-bf who killed his sister) occur before the very first game of the first movie. Meaning that either Jigsaw had started killing before we knew, or Seth was killed first. Even though Seth's murder was supposed to be an "imitation" of Jigsaw's as we see in the scene where Hoffman has a shotgun to his throat. The timeline doesn't fit.
Corrected entry: While not directly stated, it is heavily implied that the house belonging to Detective Hoffman is actually the same "Nerve Gas" house from "Saw II" (based on its structural design and the presence of the trap-door leading down into the passageways), only refurbished and fixed-up. This implies that he has moved into the property and fixed it up in order to help cover up the incident and keep the police from discovering the true location.