Revealing mistake: When Gerard Butler is driving to the warehouse to find Frank, the speedometer and the rev counter are on 0.
Suggested correction: I could not see Will's speedometer or tachometer (RPM gauge) during his drive to Frank's. What I did see (and believe you saw) was the patrol officer's instrument panel while he was parked along the road using radar. This was before he pulled out to chase Will's speeding SUV, so both gauges should have been on the far left (i.e, on "0"). [00:46:28].
Revealing mistake: When Ritchie tackles Sam down the stairs, you can get a pretty clear look at both the stunt-man and stunt-woman's faces as they fall. They then switch back to the actual actors once they reach the bottom of the stairs.
Revealing mistake: Becky calls Dan on her iPhone, as she puts it to her ear you can still see the contact info while Dan's voicemail is playing and not the actual call duration screen. (00:05:21)
Revealing mistake: When M3gan grabs the dog through the hole in the fence, the face of the person is not M3gan. (00:37:31)
Revealing mistake: When William and Jack open the door, enter the room, and walk past the helium-filled balloons (tied to a chair about 4' away), the balloons remain immobile. Due to how light helium balloons are, just opening the door or breathing nearby would be enough to cause the balloons to move somewhat - if they were actually there. (00:16:00)
Revealing mistake: In the scene wherein Detective Marquez and Senora Borden are drinking wine by the (indoor) pool, the back of Det. Marquez's head is disproportionately large. Front views of Det. Marquez often show his head tilted to the left, but rear views usually do not and his head might even be tilted to the right. Also, Senora Borden's eyes do not appear to be aimed correctly at Det. Marquez's (especially since they are facing each other with heads tilted to the right). Use of stand-in and/or green screen. (01:02:30 - 01:03:10)
Revealing mistake: The size of the spider walking off Sam's face becomes disproportionately smaller too fast compared to its size while on her cheek plus the spider's awkward movements are indicative of CGI. (00:02:20)
Revealing mistake: The $100 bills in the briefcase looked quite fake and were obviously a prop. (00:13:40)
Revealing mistake: Interior versus exterior views of the window sill/ledge are different when Brandon is aiming his rifle out. From inside the building, the window sill looks flat and the front tripod legs are close to the inside; from outside the window, the front tripod legs are over the window frame plus the ledge is layered. In some shots, it also looks like the window pane was opened horizontally to the left, but Brandon opened it by pushing it vertically upward to overlap the top pane. (01:00:43 - 01:01:41)
Revealing mistake: The 50 dollar bills that appear in the opening credits all have the same serial number (and you can find online the texture they used with great ease, just like the one for the 20 dollar bills stack). (00:03:45)
Revealing mistake: The very first shot of the movie, supposedly of Anya Taylor-Joy lighting a cigarette, does not match the following shot on the pier; the cigarette appears to be black and with a brand sleeve instead of the normal one she is smoking. The background confusingly looks more like an interior than the pier she is standing on, and the lighter is a common Bic-style one instead of the Zippo she is using also later in the movie. That's because it's actually stock footage. You can literally find the clip yourself on Shutterstock and similar websites, by the description "Close-up of the silhouette of a woman's face sticking a cigarette into her lips, igniting her with a lighter, and exhaling smoke. The grim concept of the harm of smoking in a low key." (00:01:00)
Revealing mistake: Christine closed her dead brother's eyes without actually touching them. Christine had an open hand (no cupped palm) with her fingers straight out and together; her pinkie finger touched her brother's nose, meaning her other fingers would have been too far away from his eyes and unable to make contact. (01:11:03)
Revealing mistake: The appearance of the buildings/scenery opposite of FBI Director Gabriel Robinson's office vary, indicating the occasional use of a "green screen." The angles are inconsistent (wider or in the opposite direction) and sometimes grass and/or trees can be seen where the avenue between the buildings should be visible. (00:10:05 - 00:10:38)
Revealing mistake: After the shark got Lisa, Annie climbed atop her overturned kayak and was lying with her stomach about mid-way on the kayak with her feet over the back sides. The kayak was not long enough for Annie to have her body on half of it; her legs did not look real (odd-shaped and disproportionately short/CGI). When Nic got to the kayak, Annie's toes were on top of the (overturned) kayak instead of her feet hanging over the sides. (00:36:21)
Revealing mistake: Jimmy's [Matthew Lawrence] glass of cola on the table is filled to a level slightly above the groove (mortar joint) in the cement block wall. The next front view shows the top of Jimmy's glass slightly above the same groove and the level of cola is about 2" below the groove. A little later, the level of cola in the glass is like it was earlier - slightly above the groove. A cement block wall is stationary and nobody raised or lowered the table; use of a green screen can explain the anomaly. (00:08:05 - 00:08:41)
Revealing mistake: A white truck could be seen in Tamra's rear window, following her car at varying distances. After Tamra hit Randall on his bike, the white truck was still there but gone when the camera returned to a front view of Tamra. Use of a green screen - the truck could not have gone past the accident or "disappeared." (00:03:35 - 00:04:10)
Revealing mistake: During the (second) bank robbery, the ceiling was frequently unusually close to the top of the robbers' heads (inadequate clearance), indicative of a poorly positioned green screen (or CGI). (00:16:35 - 00:17:00)
Revealing mistake: An exterior view of the damaged building was shown after Orlando's chair bomb blew through the 10th floor windows. The damage from the earlier explosion on the 4th floor could be seen in the lower left-hand corner. However, there were only two floors between the damaged floors [putting Orlando on the 7th floor] when there should have been five. IF the 4th floor was actually the 4th floor, there were not enough floors above it for the bank to be on the 12th floor. (01:20:44)
Revealing mistake: Obvious use of a "green screen" when Elvis and Dylan are sitting on the steps in the stairwell. The five distinct steps that could be seen behind them become a gray wall and the blue handrail posts to the right of the screen become oddly grouped, appearing to be parallel to the right side of Elvis' shoulder/back. (01:09:00 - 01:09:25)
Revealing mistake: The aerial view showed it was not raining during the "supercar race", but the ground views showed at least two cars getting sprinkled on (one enough to turn on the wipers). When the camera shifted to road-level, the cars and road were dry. (Suggests filming at different times). (00:31:15 - 00:31:48)