Continuity mistake: In the end, when the President is visited by the X-Men, he receives a blue binder, which is laid in front of him on the table. When they have left, you see a shot including the President's desk, and you can see that the only thing he has on the table are some sheets of paper, stapled in the upper left corner, opened up. Then the shot changes to a close-up of the President, and then back again, and you see the blue binder in front of him, closed, and the papers have disappeared. (02:01:40)
Continuity mistake: After Mark is found, he runs into Kate's arms and hugs her and her sunglasses fall off her head, but then in the very next shot they're back on her head perfectly. (01:24:50)
Continuity mistake: When Layla is hooked up to the lie detector that tracks the movement of her eye, she is looking around the room and blinking repeatedly, but the eye on the screen (which is supposed to be hers) never moves or blinks, even though the camera is still on her.
Factual error: At the very end of the film Bruce is reporting on a drive for blood donors, and Grace leads him over to the booth to give blood himself - he is even wearing a tourniquet. However, he is supporting himself on a walking stick - he is not fully recovered from the injuries he received when he was run over, which happened when he was hit by a moving car - injuries which left him clinically dead. There is absolutely no way that a person who has suffered life threatening injuries and has undergone the (inevitably) intensive drug therapies and surgical procedures involved while under treatment in hospital in the fairly recent past would be allowed to give blood. There is no way that the Red Cross (or the US equivalent) would want to encourage people who have recently been hospitalised to try to give blood. Not only would that be the height of irresponsibility, they would be wasting precious resources and staff time turning away people who would not be allowed to give blood.
Visible crew/equipment: During the scene where Neo is talking to Agent Smith in the park area where Neo was talking to the Oracle, there is a close-up on Agent Smith's face. In his sunglasses you can see a bright white screen to reflect the light onto the faces of the actors. This isn't visible in any non-reflected angles. You can also see the cameraman on the other side. (00:51:15)
Continuity mistake: In the final chase scene, the yellow Hummer starts out with an open sunroof. As it barrels through the shantytown, interior shots of the Hummer show it with a large overhead bank of storage compartments, while overhead shots show the sunroof. When the chase finally reaches Gitmo, the Hummer once again is shown with an open sunroof. (02:11:50 - 02:12:55)
Character mistake: When Charlie is calling out the brick count to Napster from the subway, he describes it as being "13 across, 4 high, 4 deep". The bricks appear to be 2 deep in the safe (13x4x2), so he could just be lumping two shelves together, which works (13x4x4 = 13x4x2x2). The problem is that when the camera pans down there are 3 shelves in the safe. This means that there are more than the 208 bricks that Napster announces. (01:33:40)
Continuity mistake: In the second half of the film, Frodo has a scar on his lower right cheek, close to his chin. Many times throughout the rest of the film the scar changes position and size on his right cheek. It also appears on his left cheek in flipped shots (most obviously on the slopes of Mount Doom when Sam is cradling his head). (02:31:05 - 02:34:00)
Revealing mistake: A quick mistake happens when Brenda and the girl crawling out of the TV get in a fight. Brenda throws the punch, the other girl falls over, and for a quick second her dress flies up too far and you can see where the makeup (that makes her look dead) on her legs end and you can see her real thigh. (00:25:15)
Revealing mistake: In the fight scene at the pier, after Freddy and Jason get thrown into the air by the carriage that smacks into them, they land on the pier in sort of slow motion. Watch Jason's left knee as he lands, you can see a kneepad.
Factual error: The geodes occurring in the mantle during the film are impossible in two ways. Firstly, there are no gaps at those depths. The pressure is approximately 3.5 million times surface pressure, and it is not feasible that such structures could form, let alone be maintained. Secondly, the crystals inside the geodes are described as amethysts. Amethysts are a purple variety of quartz, and as any undergrad geology student could tell you, there is no quartz in the mantle, it simply is not stable at such high temperatures.