Continuity mistake: When Flash is hit by the tray with food he raises his arms in disbelief. A shot later his arms are lowered and he repeats the previous movements.
Continuity mistake: When the movie begins and all the students enter the lab, Mary Jane's boyfriend nags her and she moves her arm to her shoulder, then lowers it. In the following shot her arm is raised and she is lowering it again.
Continuity mistake: When Osborn is getting ready to radiate himself at his laboratory, he throws his clothes on the floor. Their position differs between the first and second shot.
Continuity mistake: When Peter leaves Jameson's office after becoming a freelancer for him, Jameson closes the door, and at the end of the shot, the door is half-shut, but in the next shot, the door is completely shut. (00:58:45)
Continuity mistake: The day after Peter gets his powers, while he follows Mary Jane to the school, the sun changes between shots.
Continuity mistake: When Peter is testing the web on the crane, his fringe swaps between messy/ brushed /windy / still between frames in no order whatsoever.
Continuity mistake: When Osborn is drinking whiskey and hears his inner voice, is about to see the African masks and before watching himself in the mirror, his fringe swaps from messy to brushed.
Continuity mistake: When Osborn is laid on the stretcher about to enter the vault, the cables by his right shoulder change positions between shots.
Continuity mistake: When Aunt May opens Peter's sleeve to show his wound, the opening differs between frames.
Continuity mistake: During the famous kiss scene, Mary Jane's hair keeps swapping styles between shots. It changes between hairless cheek then hair on cheek, and soaked and straight to curly hair.
Continuity mistake: When Aunt May is praying, right before being attacked by Goblin, the portrait moves closer/ further away from the quilt between shots.
Continuity mistake: This is a little hard to explain. During the Unity Day Festival, after Goblin beats up the cops, the shot cuts and he turns around to face Spider-Man, who lands in front of him. The problem? He was facing the same direction as Spider-Man in the previous shot (you can tell from the background), so it makes no sense that he has to turn around when the camera cuts.
Chosen answer: "You're trash! You're always gonna be trash, just like her!" - He says this presumably in reference to Mary Jane's mother.