Continuity mistake: Batman enters Lex Luthor's room at night while he's sleeping, and completely casts a shadow over Lex. This wakes Lex up and he sits up. Batman has not moved from his position, but now in the next shots he is no longer casting a shadow on Lex's bed or body. (00:24:47)
Other mistake: While in the pool room, Zoey falls off the wall onto a portion of floor that hasn't collapsed yet and loses consciousness. This area is next to the section of floor that collapsed first. Jason jumps down to help Zoey. As he is helping her up, and onto the wall, that section of floor collapses, forcing him to grab the wall to avoid falling 20-ish stories with the floor. As he looks down drop, the section of floor that fell first is amazingly back intact. (00:59:20)
Continuity mistake: Dr. Stone mentions there is an emergency exit below the landing pad. He then asks the pilot if there is a camera underneath. In this shot, the pilot has his eyes partly closed and his lips pursed together. It cuts to a close up of him and suddenly his expression is different, with his eyes wider open and his mouth open. (00:19:50)
Character mistake: Right at the beginning of the movie, introductory technobabble. "In this canister, there's a solution of protons. The canister is attached to a rotor circuit that generates the protons to the speed of light." I believe the science genius and creator of time travel mixed up the words "generate" and "accelerate" here. (00:00:50)
Continuity mistake: When Ash and friends are entering the wharf, there are two people that change between shot. There is also a person who goes from having his right hand in his lap to having it scratching his head. (00:23:06)
Factual error: She fires the entire magazine of a Glock into the alligator's mouth. When it is empty, rather than the slide locking back and the trigger freezing, there is an audible click every time she pulls the trigger. This could not happen.
Plot hole: Dr. Seager told Beth that "It [Z] was all in her head" and only she could stop it. How, then, did her son Josh have the same "imaginary friend Z"? Moreover, if Beth had Z as a friend when she was eight years old, why didn't she remember him or have her memory jogged when Josh first told her about his friend Z? Also, if Beth told Z that they would be together forever (get married and have a lot of kids), why would Z need to go through Josh to get to her?
Continuity mistake: At the beginning of the movie, the girl gets assaulted from the back: you see at first exactly from the shot from behind that the backpack she is carrying escapes her arms, but in the subsequent shot she is still holding it. (00:02:10)
Other mistake: The opening (like most of the movie) does not make much sense, so you can pick your kind of mistake here; the special effects are cartoonishly bad throughout the big firework explosions. When John Abraham is knocked through a window by a rocket (which takes off with a 270° turn without even rising) to the face, he gets up unscathed and starts screaming for Junky and Chandu. The camera moves from them to him and he's running with the girl in the red costume in front of him (which was way behind, safely, when he crashed through the window, so already that is wrong), and then there's a wider shot. In that shot, you can tell that Adams is bumping into the same people as before and the distances between the extras are all wrong. (00:06:35)
Character mistake: Casey is sixth of six male students standing in a row to individually demonstrate a karate move for Sensei. After the fourth student, Sensei passes up student #5 and says, "Next. Casey." Sensei completely missed the fifth student, the only other beginning white belt like Casey. (00:28:45 - 00:29:10)
Factual error: This is set in 1966. The soldiers are all using the Aussie version of the M16 which was introduced in Vietnam by their military in 1967 with limited use and only became more widely used somewhat later.
Suggested correction: There's no such thing as an Aussie version of the M16, they were all made in the USA by Colt, or its contractors. I assume the poster means the M16A1, identifiable by the bolt assist lug on the right hand side and closed flash suppressor.
Factual error: Towards the end of the movie when Superman and Henshaw are fighting on the Watch Tower in space, Lois hits the sun shades to lower them so that direct sunlight can hit Superman and power him up. This is out in space with no atmosphere to filter the sunlight. The reason the blockers were there was for this reason, to keep the harmful unfiltered sun light from hitting people on the ship through the windows. However, she is able to stand there in the direct light after it's done and kiss and hold Superman without being hurt or burned by the intense direct unfiltered sunlight or its radiation.
Continuity mistake: After Wesley has intimidated the snot bully, he comes back home and finds the police. Sitting at the table, his mom holds his arm and says "Wesley, Mr. Chambers asked you a question." Mary Elizabeth Winstead has her right arm on the table, close to her body. Change of angle and she is holding the coffee mug instead. (00:45:10)
Continuity mistake: After the alien abduction, Emmet plans to lead a rescue mission and opens the gate asking "Who's coming with me?" During the sequence, the shadows change completely. At first he is not casting much of a shadow, then it reaches the metal doors, then it stops midway towards it. (00:20:55)
Other mistake: The flight attendant pulled out a wheeled serving cart as she was talking to the other flight attendant. While shown from the chest up, it was obvious the flight attendant was moving her arms for a little while and it sounded like she was placing a few glasses on the cart then stopped, but the top of the cart was filled with glasses when the cart came back into view. Also, it was not apparent from where the flight attendant had reached to get the glasses. (00:11:25 - 00:12:12)
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)
Visible crew/equipment: When Shen is telling the crew to look at the data on the disk, there is a shot of Hush turning his face to look at his computer screen. In his glasses, there is a large, glaring reflection of a green screen in them. And it's not the computer screen. (00:16:09)
Visible crew/equipment: As the camera moves forward in the opening shot, a clear reflection of a film light can be seen on the side of the fire engine.
Continuity mistake: When Nicolas Cage aka Frank Walsh first shoots a blow dart at Kevin Durand aka Richard Loffler he hits him in the left shoulder. Ten seconds later Kevin he pulls the dart out of his right shoulder. (01:23:15)
Continuity mistake: In the prologue, the Nazis storm the Bresson residence. The elder Professor Bresson is sitting at his desk, back turned to them. There's an open fountain pen next to him, right by a paper sheet, but when Bresson answers rather defiantly to the bad guys, the paper sheet suddenly has disappeared. (00:02:15)