Deliberate mistake: Dr. Chandra returns to the Leonov at the end of the film with the device that Dr. Floyd designed to cut HAL's memory circuits. He hands the device back to Dr. Floyd, who tosses it in the air and catches it when it falls back into his hand. One problem - there was no gravity on the ship at the time. (01:44:00)
Deliberate mistake: When King Shark grabs the guard from behind and eats him, he screams loudly, but nobody reacts to it, not even his buddy who just went left to fetch a drink. Later Cena and Elba kill 'silently' every other guard, but when they get to a group of three that Bloodsport yo-yos to death, it's pretty impossible that those three could have missed the carnage just a little off to the left. Then again, at the end a whole tower gets demolished without anyone noticing, so It'has to be deliberate. (00:33:05)
Deliberate mistake: When Sam is watching the security footage of his predecessors being disintegrated in the chamber, the disintegration happens the instant the coffin door is shut. However when he goes in to test it himself there is a ~60 second wait as a congratulatory video plays before the disintegration occurs. (01:00:00)
Deliberate mistake: The chainsaw cuts off the German torturer's leg and it manages to move all by itself a few feet within a few seconds, when it would just run and slowly move and stall as seen after it moves. Obviously done to increase the tension. In addition, the chainsaw looks very clean with no blood dripping and bloodstains on the floor.
Deliberate mistake: When Sook-Hee is first shown her bed chamber, just after Sasaki leaves, she slides open the door to Hideko's room to look inside. After a 5-6 second silence, a thump sound is heard and Sook-Hee quickly closes the door. Later in the movie, when this same scene is shown a second time from Hideko's perspective, the thump sound, which is revealed to be Hideko banging her doll against the wall, occurs 11-12 seconds after Sook-Hee slides the door open. (00:06:38 - 01:32:33)
Deliberate mistake: The angle of the light coming from the film projector (which was up high on the back wall) was too high to actually project onto the screen across the room. Also, people were standing in front of the screen and should have been blocking part of the projection and have light on their backs but did not. The screen operated more like a DVD player on a TV. (00:35:20)
Deliberate mistake: How does Lisa appear resplendent in that perfectly smooth wrinkle-free negligee when we saw it earlier all stuffed into her overnight bag?
Deliberate mistake: The agent is entering the office approaching his desk where a computer sits with the screen on depicting classified material. Computers left unattended go dark after x amount of time. This computer being in a federal FBI building should be logged out of and not open for everybody to see. (00:19:00)
Deliberate mistake: Before Nathan and Karen jump out of Dr. Bennett's car, Dr. Bennett's car is shown taking a sharp turn (close to 90°) and then speeding down the short but steep road. At a high speed, the car should have reached the level road within a second or two. However, Dr. Bennett talked to Nathan and Karen for a longer period of time. When the next exterior view of the car was shown, it was just reaching the intersection and straightaway. The car should have traveled a much greater distance than shown. (00:44:50 - 00:45:59)
Deliberate mistake: Wyatt is killed in a park next to El Prado museum (which can be seen in the background). Then S and McQuarry cross the street and appear next to where the bank was. This speeds the pace of the movie, but truth is that the building of the bank and El Prado are 20 minutes walking distance away from each other.
Deliberate mistake: During his autopsy in Saw IV, it is revealed John Kramer was 52 at the time of his death. Kramer's role in this film is the very early stages of his time as Jigsaw, shortly after his cancer diagnosis, which would put him in his early 50's. However, he looks far too old to convincingly be that young (Tobin Bell was in his mid-70's at the time of filming). He even looks older than he did when he was on his deathbed in Saw III.
Deliberate mistake: When Tree turns on the magnetic medical equipment, it's somehow strong enough to yank a big, heavy wheelchair up and pin Gregory in only a split-second, but not strong enough to instantly pull the screwdriver out of Tree's hand? Obviously this was done so Tree could have a cool moment where she lets go of the screwdriver and it impales Gregory... but it makes no real sense.