Corrected entry: John Kramer records his voice in order to test Cecil. This doesn't make sense: the tape player never is used because John talks face to face with Cecil about his game and the knives trap.
Corrected entry: The trap is set up for Riggs to open the door and kill Matthews, but Artie comes through the door first with the trap already set up, so shouldn't Artie have killed Matthews when he came through the door first?
Correction: This is incorrect because when you see Artie come in the door first he then presses the lever down locking the door and THEN putting the trap into action. So that the next person who opens the door will spring the trap.
Corrected entry: When Agent Strahm has finally realised where the final game is being played, he holds up the piece of paper of Jigsaw and Art outside the Gideon building. There is a hand at the top of the picture, which is a newspaper clipping, but he is holding a picture, not a newspaper. This is a reused shot of when he shows Agent Perez the picture earlier in the movie.
Correction: This is a quasi-flashback. It happens many times throughout all seven films of this series, specifically a previous shot or scene will be called back to in order to emphasize a plot point. In this case, Strahm is looking at the photo and comes to the realization that the same photograph was on the newspaper clipping he saw earlier, giving him the clue as to where the climax of the movie takes place.
Corrected entry: Most of the events of Saw IV take place during the same time as Saw III. They all involve the Jigsaw Killer. The police see the Jigsaw Killer as the source of the crimes in both movies. In Saw IV there is a completely different set of detectives working on the case as Saw III, despite being the same crimes.
Correction: At no point are the police even shown to be investigating the main story of Saw III because they do not know it is going on. They only know that "another doctor went missing from the hospital," which does not automatically tell them she was abducted by Jigsaw. The events of Saw IV are being investigated by the FBI due to their suspicion that Rigg might be involved and because a 911 call led them to the trap that occurred in Rigg's apartment.
Corrected entry: When the coroners are weighing Jigsaw's head, you can see the scale is at about 10 lbs. But when the assistant coroner takes the brain out of the scale, the scale doesn't reset itself back to 0.
Correction: Some morgues have scales that deliberately do not reset automatically, on the off chance that the M.E. forgets to record the weight before taking the object out of the scale. The scale displays the weight until it is reset manually.
Corrected entry: When Rigg awakes from the bathtub in his apartment, he grabs the sink. He only leans on it gently, and the whole thing nearly comes off the wall, revealing that it isn't attached to the wall very securely. He learns on it quite hard, but not hard enough to pull it off the wall.
Correction: Having a sink not attached securely to a wall is not a movie mistake, since that happens in real life. I've seen public bathrooms with sinks that are broken precisely because someone leaned on them when they weren't attached securely.
Corrected entry: When Rigg is talking to the little girl, he says, "How did you get those marks on your arm?" Later, in his flashback, he says, "How did you get those marks on your hand?"
Correction: I just watched the film looking for this mistake, and I can gurantee he says the same line both times ("But you're gonna have to tell me how you got those bruises on your arm and on your neck").
Corrected entry: When Eric Matthews is standing, just before he dies, look at his mangled leg with the leg brace. As Eric wiggles, you can see the skin of his real leg, perfectly healthy, underneath.
Correction: This is not a mistake. Only his ankle was damaged (when he purposely broke it), not his entire leg. So, seeing healthy skin on his leg does not constitute a mistake.
Corrected entry: The reading of the 'stomach tape' after the autopsy changes considerably between the first scene of the movie and the last.
Correction: That's because the tape is longer than the first scene led on. If the entire tape was played at the very beginning, it would have given away one of the film's twists.
Corrected entry: At the beginning, the guys at the morgue find the tape in Jigsaw's stomach because they are cutting him open. But at the end, when the detective goes into that locked room and kills the guy who shot Amanda in Saw III, Jigsaw's body is still in that room. So the guys at the morgue can't cut him up, if he was still in that locked room.
Correction: The movie is not shown in real time; what you see in the beginning of the film actually happens after all the events of the movie. After Jigsaw's game had been played out, he died, and was later transferred to a morgue, which is the scene shown at the very beginning of the film.
So how did the game begin for Rigg if the autopsy didn't yield the tape?
Rigg's game has nothing to do with Jigsaw's body and the tape inside.
Corrected entry: In the scene when Cecil is trying to get into the clinic and fakes that he left his coat, Jill turns around and unlocks the door to the waiting room, grabs the coat, and hands it to Cecil, who then charges into the room and demands the keys from Jill. Why would he need the keys if Jill never relocked the door? He was watching her the whole time, so he would have known.
Correction: He wants the keys to the medicine cabinet. They probably have methadone, among other things.
Corrected entry: When Jill went to get Cecil's jacket, she didn't lock the door behind her, yet, when Cecil forced himself in, he had to unlock the door to get into the same room his jacket was in.
Corrected entry: When inspecting the couple in the pin trap, Perez says she found out something about the three people in the traps, when it should be four.
Corrected entry: When Hoffman is talking to Rigg about it ending here, he walks in front of the camera. When he does, some of the filming equipment's shadow can be seen on Hoffman. (00:12:20)
Corrected entry: Discussing Detective Kelly's death, the two FBI agents assert that John Kramer's 'apprentice' Amanda could not have lifted Kelly in to her trap. However, this scene takes place before the bodies of Kramer and Amanda have been discovered. Therefore this announcement of Amanda's involvement comes before the authorities have any evidence of her involvement. This inconsistency is masked by the fact that the film begins with a 'flashforward' to Kramer's autopsy; however the rest of the film's action takes place prior to the autopsy and therefore prior to the discovery of Amanda's role.
Corrected entry: Lean says "Jeff" completely different to when she says it in Saw 3. When the door finally closes, she screams "Jeff!" for ages. Once Jigsaw's throat is cut in Saw 3, she stops.
Correction: I cannot understand what this mistake is suggesting. At no point in either movie does Lynn scream "Jeff!" for ages. She only says is a few times in both films, and for the most part, it matches from "Saw III" to "Saw IV". The only changes being out of necessity because we have to watch the finale's of both films at the same time, so we don't see everything from "Saw III."
Corrected entry: In the investigation of the "spike trap" scene, the rod (and the shadow of the rod) can already be seen through the left side of the crime scene photographer's neck before it even enters. (01:02:05)
Correction: I have watched the scene several times, and even gone through it frame-by-frame, and I can guarantee that at no point do you ever see the rod (or shadow) coming out of the photographer's neck before the rod enters. In fact, going frame-by-frame, you can tell that it perfectly comes out in sync with it's entrence.
Corrected entry: *Spolier* When it is revealed that the events of "Saw III" and "IV" are running concurently, we are shown that the climaxes of both films supposedly occur simultaneously in under four minutes (as evidenced by the countdown clock that Rigg sees). However, if you re-watch "Saw III", you will see that the climax of that film takes about 10 minutes to transpire. In other words, it would be impossible for everything we see at the end of "IV" to actually happen as depicted, because there is too little time. (You can also tell that they edited parts of the dialogue and sound effects when Strahm is listening to make it seem faster.)
Correction: The sequence isn't in real time. It's simply meant to demonstrate that Agent Strahm is about to enter into the fray.
Corrected entry: When Hoffman grabs the tape (from Jigsaw's stomach) off of the tray in the beginning before he plays it, at first the tray is dirty in the wideshot, then perfectly clean and shiny in the overhead closeup, then once again dirty when the shot cuts back.
Correction: No, the tray is not dirty: it's just the light reflecting off the tray.
Corrected entry: In the opening "Blind and Mute" trap, when the machine in the middle starts to pull at them both, the mute's chain is pulled taunt and causes him to pull back at it. After he notices the key on the back of the blind man's neck, he suddenly has plenty of slack on his chain to go all the way to the side of the machine and battle the blind man.
Correction: It makes perfect sense. He was going to use a recording and avoid face-to-face contact (thus preventing the possibility of Cecil identifying him later), but Cecil woke up before Jigsaw expected, probably due to Jigsaws inexperience in sedating others. Jigsaw then chose to go on with the test anyway, and simply explained the rules in person instead.
Twotall