Mistakes in the IMDb top 250
Continuity mistake: When Sonny is shot at the toll booth the front windshield is torn apart by bullets yet when the bodyguards arrive thirty seconds later, the windshield is intact.
Other mistake: When young Vito Corleone shoots Fanucci in the chest at the doorway to his apartment, in a continuous shot, a wound/blood bursts from Fanucci's white vest. When Fanucci proceeds to tear his vest open seemingly in disbelief he has been shot, there is no entry-wound, blood or hole in his white shirt directly under where the wound appeared in his vest.
4: Pulp Fiction
Continuity mistake: When they are giving Mia Wallace the adrenaline shot, they mark her chest with a red magic marker. When the shot has been given, the red mark has disappeared.
Continuity mistake: When Blondie abandons Tuco in the desert, watch the rope around Tuco's neck. It changes between shots, sometimes over his left shoulder, and sometimes hanging down in front of him. It is not due to the camera angle.
Continuity mistake: During the interrogation scene, when Batman beats up Joker, Joker's hands are holding Batman's forearms upside down (from underneath). When the frame changes his hands are now on top of Batman's forearms, then it cuts back and his hands are under again.
7: 12 Angry Men
Factual error: When the camera took a shot on a train coming to a station in Czechoslovakia, you can see electric cables above the train tracks. There was no such thing in Czechoslovakia as electrified trains in the 1940's. The electrification started in the 1950's.
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).
10: Fight Club
Continuity mistake: Close to the end when Edward Norton runs up to the front of the empty building and Brad Pitt appears, he tries to break the glass door by pushing a bench into the door, but it doesn't work. He doesn't move the bench and he then shoots at the glass and breaks it. When it shows him walking through the broken door, the bench has disappeared.