Continuity mistake: In the scene where Aunt May is outside her house, packing things into boxes, we see a close-up of her holding what appears to be a large black leather shoe at upper chest level. The next shot is a wide shot of the yard, and now she's holding it in a different position near waist level.
Continuity mistake: The spiderweb that Harry brushes aside is missing from two previous shots: from inside the secret lair looking out at Harry, and from the reverse shot looking into the lair.
Continuity mistake: In the final conversation between Peter and Mary Jane at his doorway, the lighting on his face switches in every shot.
Continuity mistake: When John Jameson and Mary Jane are walking down the stairs during John's celebration party, there are two people halfway down the staircase standing by themselves. When it does the closeup of John and Mary Jane, there are four people now standing in that spot.
Factual error: The only elevated trains in Manhattan are Metro North that goes to Connecticut and the N, Q, R, W line that goes to Brooklyn/Queens, and that line goes over a bridge. None of these trains are elevated in mid-Manhattan; and most certainly, the end of the subway line would not just be a big metal "bumper" that leads into the water.
Other mistake: The Spider-Man outfit that Peter throws in the trash appears to either have the head attached to the body or a very long neck on the mask. It hangs too far down over the edge of trash can to be the same, separate headpiece, with a short neck, that Jameson receives from the trash collector. (Though this may be a deliberate nod to the comic book, it is still a mistake.)
Factual error: Harry stumbles onto his dad's secret room and it is free of dust except for a few cobwebs. While there may have been no human activity in the room for almost two years, there were holes in the room that let sunlight, air, and insects/arachnids in, therefore there must have been airflow. With the airflow, dust or dirt should have entered the room and collected on the items.
Continuity mistake: In the first few shots of Mary Jane held hostage by Dr. Octopus in the factory, her arms above her head change from straight to bent and back.
Revealing mistake: When Dr. Ock abducts Mary Jane he is replaced by a lame CGI figure.
Character mistake: In the start of the film, the sticker on Peter's head for his work misspells the word Bleecker Street on it.
Continuity mistake: In the train scene, Spider-Man is thrown through a window and the fight continues over the broken window. When a train is coming from the opposite direction, Spider-Man leans over to avoid it, and the window isn't broken anymore.
Continuity mistake: When the car crashes in the cafe, it crashes against a column on the left. In subsequent shots the column has no damage at all.
Continuity mistake: Mary Jane holds the wedding card with her left hand. A frame later she is holding it with her right hand.
Continuity mistake: When Peter asks Mary if she wants some chop-suey, the same cab passes behind her twice.
Continuity mistake: The chip on Dr. Ock's nape is 10 centimeters away from his hair. In the close-up it's right next to the hair.
Continuity mistake: In the bank, a desk filled with papers zooms towards Dr. Ock. The papers fly away, but reappear a frame later when he tears the table apart.
Continuity mistake: Spidey and Octopus fight at the tower and a huge chunk of concrete falls on the street below. Seconds later, however, cars are seen moving around, no honks, no crashes, no problems at all, as if the falling rubble had simply vanished.
Continuity mistake: When Spider-Man stops the train his head and chest fall forward due to the momentum, but a frame later - from a different angle - he is standing still, his body against the train structure.
Visible crew/equipment: Boom mic reflected on upper part of phone when Peter puts a 50 cent coin in.
Visible crew/equipment: When Peter rides his motorbike, in the wide shots he's replaced by an obvious stunt double who wears safety goggles.
Suggested correction: Jameson must have tucked the neck up inside the mask so it would hang correctly on the wall. If he hadn't, the extra material would have bunched up under the chin area and pushed the face upward. Jameson clearly wanted the mask to "look" straight ahead.
Phixius ★
This entry isn't about how Spider-Man's costume was hung up on Jameson's wall. It's about how the mask was attached to the body portion of the suit when Peter threw it in the trash.