Revealing mistake: The dead housekeeper's body is moving its hands like it's alive after it's unwrapped out of the carpet.
Revealing mistake: In Guatemala, when Arnie shoots John, in the shots from behind Arnie's body double is noticeable.
Revealing mistake: When Anita goes to destroy their getaway car you see her pour gasoline all over the roof and hood. Then when she lights it on fire it's only burning inside the car. (01:06:40)
Revealing mistake: The structure/set-up of Richard's house (front view) doesn't make sense and can't be real. The half of the house to the right of the screen is at an awkward angle and has no windows. What little of the roof that can be seen is flat - not conducive to snowy Massachusetts. The bottom of the door to the right of the garage door is inches above the driveway pavement (elevated with no step). The deck wall to the right of the yellow door is higher than the door but the front rails only reach halfway. (00:03:25)
Revealing mistake: The cement block section of the house by the front door that Greg was painting "changed" to a flat board for a short time and then went back to the blocks. (01:05:28)
Revealing mistake: When Shin begins chopping off Jay's head, in the close-up shot a line can be seen around the part of Jay's neck that hasn't been cut yet, revealing that it is a prop head. (01:35:05)
Revealing mistake: The way the outside steps were constructed - a series of perpendicular boards with no side support - would not be able to hold weight. They would easily collapse under pressure. (00:38:53)
Revealing mistake: When they're playing kickball the first time (when Phil sucks at it), the shots change from either the sun rising/setting to fog and cloud cover.
Revealing mistake: Obvious use of green screen for buildings across the street. On and off, the background fades, and buildings appear higher or lower depending on the camera's angle. At one point, the angle of walls behind Rex (Bruce Willis) is at a downward angle, and his head is almost touching the ceiling. (00:06:10 - 00:07:25)
Revealing mistake: The use of a green screen (or other color) during most of the cafeteria scene is obvious if you watch the people in the background instead of the main characters and is flawed in a few ways (e.g, varying angles, greater distance, continuity of a person, etc). For example there is a man wearing a blue shirt/tan pants and carrying a briefcase walking down the aisle toward the Good Boys' table. When the man is walking along the wall that is behind the Good Boys, he is further ahead than he is when he is picked up again. Also, this man shows up in front of Max when Max is walking to Soren's table. The man also appears walking along the back wall with a woman. Watching the wall behind Thor and Lucas, it is sometimes at an angle and other times looks more distant. Some of the people would essentially be walking "out of the wall" in order to appear where they do (e.g, the boy with a backpack).
Revealing mistake: When Nathan and Theresa are talking on the front porch, the background is fake (and mostly blurred). The white picket fence just doesn't look real. A hanging plant on the porch sways a little from wind but the two nearby trees (leaves/branches) are stationary. Next, one tree gets a gust of wind while the other one does not and the remaining trees in the background do not show any movement. (00:13:50)
Revealing mistake: After most of the people trying to hang onto other people holding onto the ascending helicopter fell off, a downward view from the helicopter showed a man effortlessly hanging onto the landing skid and a woman just as effortlessly grasping his jacket's shoulder. (00:02:50)
Revealing mistake: Ron leans against a barrel and sets in motion a series of events leading to an explosion. For being able to tip it with such a modest push, it is obvious it was empty (confirmed also by how it bounces). (00:02:20)
Revealing mistake: After breaking Zapan's nose, Alita jumps on the table of two guys and trash talks them into a fight; before they attack, the two bottles of beer on the table are different, one being the generic red and white Cerveza, the other with a peach colored label. When she kicks the CGI bottles, those are two identical Cerveza ones. (01:01:15)
Revealing mistake: A lot of the CGI was quite good and, even if not totally realistic, was interesting and exciting to watch. However, the man supposedly rappelling (or abseiling) down the mountainside was obviously not there - his feet didn't touch the mountain. (00:36:10)
Revealing mistake: Aladdin uses the rope horizontally to move past the fire on the floor. Obvious CGI flames get to his clothes and to him, but he does not break a sweat or feel any pain. (00:17:55)
Revealing mistake: When Shaft thinks about the address of the drug supplier, he stares at a newspaper clipping on the wall. The clipping is zoomed in close for over 1 second, and it's more than enough to spot the famous words "Lorem ipsum..." at the beginning of the article, revealing the clip to be just a movie prop with the industry standard filler text jibberish. (00:27:10)
Revealing mistake: In the semi-POV shot showing Elena's face as the SUV rams into their getaway car, the passenger window is open - which would make no sense in the heated car chase with bullets flying all over the place, and is not consistent with the rest of the scene either. Just helps filming. (00:24:35)
Revealing mistake: When Tree kills herself by throwing herself out of a plane, in the shot where she lands in front of Carter and Danielle, it's very blatantly obvious she was filmed on a greenscreen and comped in. The lighting on Tree doesn't quite match the lighting of the scene, and there are very obvious and unnatural hard lines around her hair where the background was rotoscoped/keyed out.
Revealing mistake: When Phil approaches Michael's grave, water ("rain") has already accumulated only in front of the grave. When Phil is kneeling by the grave, streams of "rain" fall behind him and in front of him, but not directly on him. (00:25:03)