Revealing mistake: While Bishop and Steve McKenna are practicing with various firearms, a slow-motion shot in the film of Steve shooting a .50 caliber rifle shows that, while the sequence depicts him firing "live" rounds, the extracted shell casing is from a "Blank" cartridge (evidenced by the crimped forward portion of the brass casing). (00:34:15)
Revealing mistake: When Bella calls Rosalie, you can briefly see the cell phone screen before she puts it to her ear. The lock screen is still visible, showing she didn't dial anything. (00:55:45)
Revealing mistake: In the scene in the Russian bar, Dutch takes the bartender's gun. When he turns to hit her, the face of the stuntman replacing Alan Tudyk is visible. (01:03:40)
Revealing mistake: At the start, just as Moreau rides up the stone road leading to the monastery up ahead, before he passes the two guards we can see that it's a flipped shot - note the backwards license plate number.
Revealing mistake: When we see the new recruits at boot camp, they are wearing M1 Helmets. But if you look closely, they have rivets through the sides of each helmet where the chinstrap bales would be. In reality, the M1 helmet chinstrap bales were and continued to be welded onto the shell of the helmet. This indicates the helmets in the film are probably plastic replicas with the bales being riveted in place.
Revealing mistake: When Bethany comes home from the hospital after losing her arm, her dad drives them to the back of the house to avoid the reporters. Bethany has her arm covered up with a throw so it can't be seen. When she gets out of the car, you can clearly see the outline of her entire arm underneath the throw.
Revealing mistake: When Kato is driving home after the argument with Britt about making coffee at the office, Kato is jerking the steering wheel randomly like a child pretending to drive despite it seeming they are just driving straight down the road. (00:56:30)
Revealing mistake: Just before Charlie is stabbed you can see the "blood pack" under his shirt.
Revealing mistake: In the scene where Harry and co. are in the Room of Requirement, at several points during this scene, you can tell by the way the light shines that Harry's glasses are missing their lenses, especially in close up shots of Harry.
Revealing mistake: When Blackbeard threatens Jack with a pistol, he is heard cocking it, but when he holds it up to the camera we can see that it is only on half-cock. A pistol cannot be fired in the half-cock position, nor can it be loaded in the fired position, implying that either it is not loaded, or a technical error has been made by the film makers.
Revealing mistake: When Brian is racing the GT3RS through the mock up track we have a shot inside while he is doing a hard left. Look at the dash and the speedo on the far left is at 0 while the rev counter in the centre moves. Evidently he was stationary and just revved the car for the shot. (01:04:25)
Revealing mistake: During the opening musical number, right before Gary joins the large group of people for the dance, he accidentally kicks Walter out of frame. Watch closely though. His foot comes nowhere near Walter when he supposedly "kicks" him.
Revealing mistake: When the apes jump out of the lab windows out to the street, they don't cast a shadow on any of the glass except the ones on the ground floor.
Revealing mistake: Every time Colter finds the bomb, the cell phone used as the detonator, is running a Adobe Flash movie named "HISTORY.swf" on its screen. The Adobe Flash Player logo is visible in it. When he removes it the first time and tries to call back the bomber, it's nothing but a Flash animation sequence playing on this mobile. (At about 01:11:20) Finally he finds the secondary mobile at the back of the bomb, and this too has a HISTORY.swf playing in it. (00:15:30 - 00:55:00)
Revealing mistake: When E.B. Is drumming along to Dynamite at the "Hoff Knows Talent" audition there is an audible bass drum beat but via several overhead shots you can see that E.B.'s feet do not reach either the bass drum or hi-hat pedals.
Revealing mistake: When Tigress is hatching a plan to escape Gongmen Tower after they have been trapped, she looks out over the wall. But take a close look at the archers: they all move in perfect sync, indicating the same animation models were used for all of them.
Revealing mistake: While driving the Mercedes to the house of grandma, the gauges on the dashboard show speed is zero and the engine is cold.
Revealing mistake: When Sweet Pea, Rocket and Blondie are sitting in front of their mirrors and discussing how Babydoll saved Rocket from the cook, the camera starts behind them, pans to the left, through the mirrors and out the other side. Before the camera passes through the mirrors, if you look closely at the girls' backs, you can see that they are slightly out of sync with their 'reflections'; it is obvious they used doubles to sit with their backs to the camera and copy the actual actresses.
Revealing mistake: When the car Paul is driving spins out of control and flips, the roll bar is visible through the back window.
Revealing mistake: The hero breaks through a window from a balcony into an apartment. The way it shatters and crumbles into such small pieces indicates that it is breakaway glass, not regular window glass, obviously for the safety of the actor during the stunt. (00:55:25)