Best movie mistakes of 2004
Factual error: As Ben is clinging to the staircase while it is falling apart, there is a close-up of a nail being pulled out of the wood. This nail is round-headed, rather than square as it would have been over 200 years ago. It's also shiny instead of rusty, which indicates that it's galvanized. Galvanization as an industrial, metal-preservation process was not patented until 1837, and was not used in building materials until well into the late-1800s. Since the film states the staircase was made by "the Founding Fathers, " and there was no galvanization of iron nails in any industrialized nation in 1780s-1830's, this is a huge anachronism.
Plot hole: Harry tells Doc Ock that in order to find Spider-Man he must find Peter first. Doc Ock finds Peter with Mary Jane in the cafe and throws a car through the window straight at them, then later throws Peter against a brick wall. Any normal person would've been killed instantly (or very badly injured), and Doc Ock doesn't yet know that Peter is Spider-Man. Given that Peter is his only lead on Spider-Man, it makes no sense that Doc Ock would try to kill him.
Continuity mistake: When Malfoy and his friends bother Ron and Hermione, Harry shows up and messes with the three boys. He grabs hold of Malfoy's feet, lifts them in the air and pulls him across the snow. In the first close-up of the soles of Malfoy's boots, not a speck of snow is on them, though he was just walking in it! Then in the next close-up, his feet still in the air, the soles are now covered in snow.
Visible crew/equipment: As Achilles' ship nears the Trojan shores, Agamemnon snidely asks, "What's the fool doing? He's going to take the beach of Troy with fifty men?" At the start of the next shot, as the camera begins to pan down, on the far right, just beside a person's (who is dressed in blue) head is a metal bullhorn (ie. used to give instructions to cast/crew, and which definitely doesn't belong in this time period).
Visible crew/equipment: As Sam and Rhonda have Fiona's car confiscated, when Fiona runs out shouting, "I can pay for those parking tickets!" the crew's black mat is laid out on the walkway, but in the overhead shot when she tries to run away that mat is gone. (Visible on fullscreen DVD.)
Factual error: The aircraft flying to rescue the British Royal Family are described as belonging to "an RAF search and rescue squadron." However the middle aircraft has white and green striped camouflage painted on it, which is a pattern only used by aircraft in 845 Naval Air Squadron (a Royal Navy unit).
Continuity mistake: When Hutch tackles Starsky to the ground after his gun goes off in the disco, Starsky's badge falls to the ground beside his head. Hutch grabs it and holds it up, telling people to calm down, but when the shot returns to Starsky the badge is still there next to his head.
Continuity mistake: Hellboy tosses Dr. Manning through the quickly-closing door to escape the pendulum on the bridge - he barely makes it under. Hellboy then spends thirty seconds dodging the pendulum, but when he dives for the door it's still closing at the same point and speed - just enough for him to pass.