Continuity mistake: In the scene where we first see Jameson sitting at his desk watching the other guy explaining something on the whiteboard, Jameson's cigar keeps constantly changing between shots from being in his mouth, to being in his fingers and being in the ashtray, all this happens when Jameson's secretary first interrupts him and tells him to watch the anger.
Continuity mistake: When the sacks of money are handed over to the guard at the back of the armored truck, note the license plate number begins with "13022" but then it changes to "48321" during the rest of the scene. (00:49:20)
Continuity mistake: When JK is receiving a marketing lesson in his office, the amount of water in his glass increases between shots instead of decreasing.
Continuity mistake: When Gwen is hanging on the edge of the building, the table that slides towards her swaps from being worn out and filled with scratches to new.
Continuity mistake: When Captain Stacy gets to the street where Gwen is about to fall down, a police van is parked behind him. However, in the next shot, the van is gone.
Continuity mistake: Just before Eddie gets the black suit, he enters the church and is dry, but he should be wet because of the rain outside.
Continuity mistake: Right before Sandman is turned into sand he raises his hands to protect himself. A shot later they're lowered, and he raises them again.
Revealing mistake: When Peter and Harry are fighting into the Goblin's lair, stunt cables are visible on their backs holding them.
Continuity mistake: When Peter is talking on the phone with Dr. Connors in his apartment, the hand that's holding the phone switches between shots. In the first, it's his right hand, immediately after that, it's his left hand, and in the third shot it reverts back to his right hand again.
Continuity mistake: When Gwen is free falling, her hair moves wildly except for the part where she is about to be crushed by two pieces of concrete, where her CGI hair is completely still.
Continuity mistake: Eddie's watch switches hands when he's being taken over by the symbiote.
Continuity mistake: In the scene where Marko falls into the molecular chamber and the machine starts up, turning his insides to sand, we follow pieces of sand into his left hand but, going in the same direction we went in, we come out of his right hand.
Continuity mistake: In the scene where Spider-Man is being given the key to the city, the view as the camera sweeps the band, it shows a full row of members on the top left, but when you see the band from the park angle (during MJ's conversation), there are less band members.
Continuity mistake: Before Sandman is turned into sand, the craw-like machine lifts up tons of sand but it never gets in his eyes nor sticks to his shirt.
Continuity mistake: When Peter gets Eddie out from Venom you see a lot of symbiote stays on his chest after he finally gets out from it, but in the front shot of the symbiote you see no remnants on his chest.
Continuity mistake: In the scene just before Mary Jane throws a hollow brick onto Eddie's head, his back is briefly shown where we can see that he is not wearing any dress under his venom suit. But later at the end when Spider-man tries to save Eddie by pulling him out, his dress comes back on him.
Plot hole: When Harry's pumpkin bomb exploded, disfiguring his face, there were also more pumpkin bombs around him. This explosion should have caused them all to explode, which would have killed Harry.
Suggested correction: It's entirely dependent on how the pumpkin bombs function and how they're built. They're likely built to be able to withstand a certain degree of outside force and heat so they wouldn't just randomly explode during a superhero/villain battle. They also don't seem to function like regular grenades... there seems to be electronic components to them. So it's entirely possible they can't go off until they're activated because certain components inside haven't mixed or been armed. Their rules are just too vaguely defined for this to be a valid mistake.
That's a good point.