Revealing mistake: Each crew member has a monitor on their spacesuits that they use whenever they are exploring the caves. Whenever the monitor is shown, each crew member's individual heartbeat is shown in the lower left corner of the monitor. But no matter which heartbeat is shown, every time a heartbeat on the monitors is shown, it is always the exact same heartbeat, despite the various changes in panic and stress throughout the movie.
Revealing mistake: When the train plummets into the basement, the windows never seem to smash nor crack, nor does the paint on the train ever seem to scratch the slightest bit. (01:34:15)
Revealing mistake: You can see the blue screens on Bruce Banner's glasses when Tony Stark is talking to him about embracing the Hulk rather than disliking it. (00:57:40)
Revealing mistake: In the opening shot, when it pans towards Mr. Leonard and the old lady, the street lamp that is positioned to the right of Mr. Leonard's car begins to pass in front of the car even though it is placed on the other side of it. (00:00:20)
Revealing mistake: At Coney Island, K zaps J's neck with a tazer and knocks him out. J is seen falling onto his back on the ground, where the background fades out to show time passage that he wakes up sitting in a chair in MiB head quarters. The effect was cool, but the way it was done reveals itself. J wakes up in a leaning back seated position looking up as his head is slumped back over the chair. It is obvious they used this part of the footage to show him lying flat on his back on the ground at Coney Island, only you can tell he is not lying flat on his back. (00:42:55)
Revealing mistake: When Katniss is blown back from the explosion, her stunt person is visible. This can be proven because the stuntperson's skin tone is different and her hair is not in a braid. It is in a ponytail. Wires can also be seen pulling her to give the illusion that she was blown back from the explosion. (01:33:00)
Revealing mistake: Right at the end of the fight between Selene and the Uber-Lycan in the vampire coven, the Uber-Lycan throws Selene into some wooden panels, knocking her unconscious. As she travels through the air you can tell that she is suspended by wires; she travels far too slowly towards the wooden panels for someone who was just thrown. (00:48:35)
Revealing mistake: When Blake and Gordon watch Bane on TV during Gotham's siege, a grey (sometimes white) square is reflected on Gordon's glasses. It's either a lighting screen or the proof that the TV is turned off and the image on it is added on post-production.
Revealing mistake: When Snow White rides the white horse bareback to the dark wood. In the last few frames as the horse gets trapped in the mud you can see a very thin set of reins attached to the horse's head.
Revealing mistake: When Dredd throws Kay onto the table, Kay is supposedly handcuffed, but his hands spread apart way further than they should have.
Revealing mistake: When Alice shoots the zombie in the blue dress, we get a frontal shot of the gun. Pay close attention to her trigger finger: it doesn't move at all, while the gun does fire.
Revealing mistake: When Picasso removes the first finger from Fan Yau Lee's hand, you can see that there is no blood on the instrument used.
Revealing mistake: Right in the beginning of the movie, we see young Viktor holding a gun to a young girl, about to shoot her. The gun is a revolver and as it comes into focus, you can see there are no bullets in the gun. This is part of a later scene in the movie where Viktor kills his first two people. As he's shooting, you can again see there are no bullets in the gun. (00:01:20 - 00:23:10)
Revealing mistake: After Hoyt is shot by the cops, Will escapes through a window. One cop fires an M16 at him and Will tries to go over some rails, which just break and he falls on garbage. In one shot where he lands, you can see the face of Nicolas Cage's stunt double. (00:51:40)
Revealing mistake: As John is walking up to the view portal and sees the girl being attacked by the sleeping bag zombies, watch his shirt. As he stops, there is a texture glitch in the animation and his shirt flickers a few times. (00:10:10)
Revealing mistake: When the three characters are playing with legos and Matt is told to start playing music from his ipod, you can see that the sound is off and the ipod is paused when the music is apparently playing.
Revealing mistake: Considerable efforts were made for this film to have Joseph Gordon-Levitt resemble Bruce Willis (colored contacts, nose prosthetics) since they are playing the same character at different ages. Yet the two actors' ears remain distinctly different. Bruce Willis's ears are much larger than Joseph Gordon-Levitt's, and Joseph Gordon-Levitt has connected ear lobes while Bruce Willis does not.
Revealing mistake: In the scene after Will leaves the girl at the train station, the scene cuts to a downtown district. Many of the extras used for that scene are seen watching the scene being filmed. (00:57:00)
Revealing mistake: In the car chase, the stunt ramps on the ground so that both cars can easily race over the curbs instead of destroying their wheels. (01:20:20)
Revealing mistake: When the officer on the bike chases Wilee, the door to a taxi opens and the officer collides with the door. You can see that the window had been removed from the door to make sure the actor doesn't get injured. It certainly wasn't rolled down because the frame isn't even there. (00:18:00)