Visible crew/equipment: When the doctor wants to study Electro, a green screen and some other things are reflected in his glasses. (01:14:10)
Factual error: Towards the end of the film, Spiderman takes his web and uses it to connect to the different power conduits that Electro blew open, ties them together, and power the city back up. Electricity uses several different wires, and crossing them would cause things to blow up or short out. What should have happened when Gwen threw the switch was another power failure, instead of the city's power being restored.
Continuity mistake: During the battle with Green Goblin, when Gwen Stacy is falling through the clock tower, there are dozens of gears and other pieces of various sizes falling with her. However, when she lands, only a few small gears and pieces land alongside her - all the other debris that were falling have seemingly vanished. (02:01:20)
Suggested correction: That part of the scene is SO dark that it's really hard to tell; they do show some gears and pieces land after she does and there are some gears and pieces next to her when he walks to her. I wouldn't say there's none, but I'd say it does seem a disproportionately low amount considering how many giant gears were falling.
Given that even you admit in your correction that the number of gears seems disproportionately low (which it is - we only see a few small pieces landing when there were dozens and dozens of pieces in different sizes falling), I think amending the wording through a word-change is a better option than trying to correct the mistake itself. Because there is still a mistake here. Going to go ahead and do that after I post this response. (Might take a few days to change, though).
Continuity mistake: In the scene where after Peter gets his diploma and has a chat with Gwen, he is carrying a backpack on both shoulders. As the scene continues it switches to one shoulder then both several times. (00:15:50)
Plot hole: The crux of the plot (one of the many plotlines, that is) is that Harry Osborn hates Spider-man because he refused to help him when he is quickly dying of the same genetic disease that killed his father. You can see the problem in this sentence already; he is a teenager, but he's dying super-quickly (he already has a large ulcer on his neck) of a disease that didn't bother him with severe symptoms before and that took away his father at 63. No reason is given of this sudden outburst in Harry's case, in fact nobody even acknowledges that such a difference exists.
Visible crew/equipment: In the scene when Spider-Man is chasing a truck stealing OsCorp's plutonium vials, the truck, driven by Aleksei Sytsevich, crushes one of the police cars. The scene cuts to the left side of the truck crushing the police car. A moment later, it cuts to another angle. Here you can see the camera equipment on the left side of the truck. (00:08:20)
Continuity mistake: After Peter gets his diploma and has a chat with Gwen, the sun changes between shots.
Other mistake: The main events of the film presumably take place in May, since we see Peter and Gwen graduate in the beginning. After Gwen's death, Peter is shown mourning through autumn and winter-like weather. However, near the end of the film, a news reporter says it's been only five months since Spider-Man disappeared. This would put the last fight with Rhino in October, and mean it snowed in the middle of summer.
Audio problem: During Electro and Spidey's final battle, after Spidey breaks the yellow pipe Electro says "Is that all you've got?" but his lips aren't moving. (01:51:15)
Continuity mistake: During the battle between Electro and Spidey, the chip on Electro's head swaps from being on the right side to being on the left. It is specially noticeable when Electro overloads.
Continuity mistake: When Peter and Harry chat by the river and Peter jumps to the other side of the railing, his left hand is either atop or below the railing, depending on the shot. (00:41:30)
Continuity mistake: When Gwen dies, the position of Spidey's left hand is inconsistent in almost every shot: Moving between her temple and cheek back and forth. Also, when he says "Stay with me" his right hand suddenly appears / disappears randomly around her head. (02:02:05)
Continuity mistake: Peter is in bed watching the closet with his dad's briefcase inside. He stands-up and his earplug falls out, but a shot later it's back in. (01:01:10)
Continuity mistake: Peter opens the closet and throws a red jacket on top of his dad's briefcase, then closes the closet. Several shots later, when he opens it again the red jacket is gone. (01:00:05 - 01:01:05)
Continuity mistake: After Electro launches Spidey against the police car, the huge dent on the door gets smaller between shots. (00:55:40)
Continuity mistake: After Aunt May takes a picture of Gwen and Peter they're standing side by side. A shot later they're a meter and a half away from each other. (00:15:55)
Continuity mistake: When Aunt May takes a picture of Gwen and Peter she places two left fingers on the camera. When the angle changes there's just one. (00:15:50)
Continuity mistake: After saving a bus, when Spidey confronts Rhino the big puddle beside him disappears between shots. (00:13:45)
Continuity mistake: When the fake pilot stands up to punch Peter's father his parachute disappears. (00:05:30)
Factual error: A helpful automated voice from Oscorp informs the robbers that "Plutonium-838 is a radioactive material and is highly explosive." No it's not. It is radioactive obviously, but it is not some volatile explosive. (00:09:10)
