Corrected entry: In the scene where the car comes crashing through the window, when Peter picks up Mary-Jane, her back hits her chair, causing it to fall. But in the next shot, her chair is sitting fine, on all four legs.
Corrected entry: Window in Peter's apartment at the end has a red and blue segment, something which wasn't present earlier: a symbol that Peter has accepted who he is.
Correction: Those panes are there for the entire movie.
Corrected entry: During the clock tower fight scene, Doc Ock breaks the minute hand into two pieces and throws them down at Spider-Man. When the camera switches to Spider-Man, he dodges two pieces and gets hit by a third piece of the minute hand.
Correction: Spidey dodges both halves of the minute hand. The third thing that hits him is Doc Ock's tentacle.
Corrected entry: Peter Parker's blonde neighbor finally gets up the nerve to approach him, asking him if he would like some chocolate cake. She and Peter are then seen having just finished the cake, but the crumbs show that the cake was yellow, not chocolate.
Correction: The cake's always seen to be vanilla with chocolate icing - not entirely random to describe it as chocolate cake.
Corrected entry: Right after the scene where Mary Jane is kissing her boyfriend upside down on the couch, there is a quick shot of a city block, that is shown backwards. This can be detected from the vertical "park" sign that has the letters reversed.
Correction: On first glance this is correct, but the shot actually shows a reflection of the street in a large window, hence the text is reversed, it is not a reversed frame.
Corrected entry: In the scene where Peter Parker is visited by the girl from across the hall, she offers him a piece of chocolate cake and milk. A couple shots later we see white/yellow crumbs on the plate, not chocolate.
Correction: Apparently you've only seen one kind of chocolate cake. There's that yellow kind too with chocolate icing. You can find it in the store.
Corrected entry: When Peter Parker saves the child from the burning building, while he is running with her in his arms, you can see that in some shots she is a doll.
Correction: No, she's not. There is nothing that would indicate that she was replaced by a dummy.
Corrected entry: When Peter makes his final pizza delivery before being sacked, the receptionist refuses to pay because he is late. The clock behind her states around 3.04. When Peter arrives back at the Pizza shop, the guy is firing him but the clock behind Peter reads 2.10, some 54 minutes before he is late delivering the pizza.
Correction: It's not unheard of for one clock or another to be wrong.
Corrected entry: In the new "2.1 extended edition" there is a scene where Spider-Man and Doc Ock are fighting on the side of the train and people on the loading platform have to scatter to avoid being hit. But if you pay attention, the train is on the opposite track that it is on in both previous and following shots.
Correction: In the features on the 2.1 DVD, the producers say that the theatrical release will always be the "real" Spider-Man 2, and that 2.1 is just something they put together for the fans. The extra shots in the train scenes was taken from footage discarded early in original production, so they had to basically put all the effects together from scratch using spare background and coverage shots. A few slight mistakes would be expected.
I feel like this isn't a valid correction. 2.1 is still a publicly available version of the movie (that's been included in basically every single DVD/Blu-ray set since it came out), and it's still a mistake within that publicly available version.
Corrected entry: Just after Peter decides not to be Spider-man anymore, he is seen walking down the street without his glasses. He trips and falls three times, apparently because he can't see properly without them. The first time he stands up, you can see his right hand reaching for the glasses on his belt loop. He never takes the glasses, nor does he put them on, he just reaches for them and grabs them. The second time he stands up, neither hand reaches for the glasses. But the third time, he reaches for and grabs the glasses again. you can see that it's the same exact bit of footage as used for the first time. Then finally he puts them on.
Correction: It's a montage. During a montage, many times a director will show several shots of the same event happening. In this case, Peter is shown tripping from three different angles and the length of time shown from each angle varies from shot to shot, but it's all the same fall.
I've seen another correction where it is stated that because the location Peter is in changes from fall to fall (details in the background change when they shouldn't), these are in fact distinct falls/events that occur at different times. Could still be consistent with the montage idea though.
Corrected entry: Unlike the Green Goblin in the first movie, Doctor Octopus does not have superhuman strength. He should not be able to handle the amount of hits that Spiderman (who is incredibly strong) lands, especially the ones to the head. Even if Spiderman was holding back a little for some reason, Doc Oc wouldn't be able to take that much of a beating.
Correction: In the comic books, Doc Ock absorbed some of the energy from the explosion that fused the mechanical arms to his body, thereby making it possible for him to stand up to Spider-Man in a fight. He wasn't anywhere near as strong, but was stronger than the average human. This is never explained outright in the movie, but it's implied by the very fact that Ock is going toe-to-toe with Spidey.
Corrected entry: In the bank Doc Ock throws around huge bags of gold bullion coins. There is no way a modern bank (or anyone else) would store gold bullion coins in bags.
Correction: This movie is a representation of a comic book world, not reality itself. The theme of gold bullion in bags heaped up inside safes is a classic hallmark of the Genre.
Corrected entry: Why does the driver of the train continue to proceed along the track? Surely he would stop as soon as he heard the noise of Doc Ock and Spiderman fighting?
Correction: Why would he stop? It would make much more sense if there's a problem to try to get the train to the next station, where people can actually get out, rather than leaving them on an elevated track with no possible exit.
Corrected entry: In the opening scene of the film when we see Peter almost hit his pizza boss, if you slow this part down you can see in one shot, Peter's boss has his hands wide open, and in the following shot he is checking his wristwatch. (00:03:20)
Corrected entry: After he's unmasked by Harry, Peter asks for the location of Doc Ock's lair so he can rescue MJ. How would Harry know it was an abandoned warehouse on the river? His exchange with Doc Ock a few scenes earlier never mentioned it.
Correction: Not everything is captured on screen. They could have had an exchange some other time.
That would make no sense for Doc Ock to tell Harry where his second lab was since he was wanted by the police and needed to create another reactor without any interference. Plus, if Harry knew where Doc Ock's lab was, he could have just gone there to give Doc Ock the tritium himself rather than the exchange taking at Harry's place.
Corrected entry: When Dr Octavius first meets Peter he says, "Intelligence is not a privilege - it's a gift to be used for the good of mankind." But in the scene towards the end of the movie where Doc Ock has realized that Spiderman is Peter Parker, Peter says, "You once spoke to me about intelligence, that it was a gift to be used for the good of mankind." Doc Ock nods his head and says, "A privilege." He's contradicting himself.
Correction: Character mistake - he misremembers. Not surprisingly, considering the stress he's been under lately.
Corrected entry: When Peter transforms into Spiderman to get to his next delivery quicker, two kids run out into the street. The kids reach the curb, then from Spiderman's perspective, they reach the curb again. (00:04:55)
Correction: These "repeat scenes" are common movie making/editing techniques. Its purpose is to show exactly what you've just pointed out, to show two scenes shown from two different points of view. These are not movie mistakes.
Corrected entry: After Peter has bought down Doc Ock in his warehouse, he brings him to his senses by reminding him that he once told Peter "intelligence is a privilege, not a gift", and Doc Ock agrees. However, at the start of the film the Doctor actually said intelligence was a gift, not a privilege.
Correction: He doesn't say "not". He says, "A gift, a privilege", saying intelligence is both of those. Therefore at the end it wouldn't matter what order it was said in.
When Peter first meets Otto, he is told that intelligence is not a privilege but a gift to be used for the good of mankind. Near the end when Peter reminds Otto of what he said, Peter says "you once told me that intelligence was a gift to be used for good" to which Otto replies "a privilege" which contradicts what he originally said in the beginning. I do not believe this is a 'character mistake' though. It's genuinely a movie goof as other language versions of the movie have Otto saying "not a privilege" at the end. It wouldn't make sense for Otto to sincerely misspeak at such a crucial moment in his character arc resolution.
Correction: That was a chair behind her.