Revealing mistake: During the scene in the bar, the first shot shows some kid playing an arcade of some sort, and the shot continues to scroll from right to left. However, all the writing (ie. the arcade machine, t-shirts, chalkboard, and various signs) are all backwards, which means the shot is flipped.
Continuity mistake: At the beginning of the film when the shark attacks the divers, you see in one shot that the shark already had a burned scarred face. The shark doesn't get set alight until later in in the film. This scene was one of the last ones to be filmed.
Suggested correction: The burned and scarred shark face is from the explosion at the beginning of the movie when the water skier's boat exploded.
This correction's false - the attack on the water skier's boat occurred well after the opening attack on the divers.
Continuity mistake: After explaining what they saw when Terry's mom's boat exploded Tina asks if they can leave. Brody then puts his hand on the porch column on the left side of it. When it cuts his arm is resting on the right side of it.
Continuity mistake: When the teenagers are near Cable Junction on their wrecked boats, they see Chief Brody coming towards them on the Police Boat. We then see a close-up of Brody, and from his view he is approaching Cable Junction and the teenagers from front-on, with the teenagers on the right. When we see Brody approaching them as seen from Cable Junction, he approaches them from a completely different direction. He comes from behind them as if he approached from a different side of the island.
Continuity mistake: In the scene where Chief Brody comes home drunk, Deputy Hendricks comes over to express his sorrows. When he's leaving/already left, Both Ellen & Chief Brody comment on Hendricks as "Poor Jeff." In the first Jaws film, Brody calls him Lenny. Jeff is actually the first name of the actor who played Hendricks.
Suggested correction: It was a retcon from the filmmakers. Originally his name was Lenny, and then they changed it to Jeff. Same thing with The Mayor's children in the first movie. In the sequel, he only has one son; Larry Jr.
Not really a retcon, simply a mistake. Not every change, intentional or not, can be hand-waved away as a retcon.
The correction is valid. The person who submitted the mistake didn't watch the scene. They never said "poor Jeff", it was "poor Hendricks." But both Martin and Ellen call him "Jeff" in the scene and his name is said 3 times. Plus, if you read over the original script, the name "Jeff Hendricks" is mentioned 4 times.
Factual error: Whenever we see the shark gliding through the water, we only see the dorsal fin, never the tail fin. Realistically, we should see both fins above the water in at least some shots - especially when the dorsal fin is fully out of the water.
Visible crew/equipment: When Brody is rigging the winch it shows an underwater shot, presumably from the sharks point of view, if you look attached to the kids boat's there is a wire anchoring them down.
Continuity mistake: Brodie is racing in his vehicle down the beach to investigate an incident, driving to our left. He then gets out of the car and is shown running down the beach to the left. Unfortunately, the scene was shot with Brodie running to the right. The editor simply reversed the film so Brodie would be running the right direction. You can see backwards writing for about 2 seconds.
Continuity mistake: After Chief Brody is fired from his job, he comes home drunk. No beer cans can be seen spilling out of his car or on the ground. The next day when he is taking his wife to work, there are several empty beer cans on the ground. Where'd they come from?
Continuity mistake: Chief Brody and his raft disappear from under the shark when it catches fire. Understandable, as they were burning the model shark for real, but still poorly edited.
Character mistake: When Dr. Elkins is measuring the Killer Whale, she says "111 centimeters" followed immediately by "68" (centimeters). But her arm spread shown when she says that is not 111 centimeters - about 3.6 feet (1+ YARD wide). It's more like 2 feet. The "68 centimeters" is actually more accurate for the shot though: 26 inches, which is shown.
Other mistake: The dead Killer Whale washed up by the lighthouse was visible from the teens AND in their line of sight while they sat on the shipwrecked boat, also their Catamarans they pulled onto the sand were literally 100 feet away - as seen in the wide shot, but yet it was a surprise when Tina and Eddie come upon it. There's no wrack line showing in the sand so the whale didn't "just wash up "
Continuity mistake: The boat Tina's Joy is hit on the sideboard by the shark and a portion splits off. When they are rescued the boat is intact.
Continuity mistake: Brody fires six shots from his revolver after coming down from the tower. He ejects the shells on the beach. Then he squats to pick them up and there are many more than six.
Continuity mistake: When the young guy is fiercely swimming back to the sailboat, the shark yanks him under a few times as he struggles to climb back in the boat. Suddenly there is a huge pool of gushing fake blood floating all around before he's even pulled back under.
Factual error: Several times Chief Brody was seen to both transmit and hear the boat radio without him taking his finger off the mic button. If the button is pressed you can transmit, but not receive.
Continuity mistake: While the shark pulls the police boat the sun changes between shots.
Continuity mistake: While the shark attacks the waterski boat the sun changes between shots.
Revealing mistake: When Chief Brody sees the driftwood in the water, he sits down and takes his shoes off to wade in. As he sits down, his butt is already wet, even though he sits in dry sand.
Factual error: Brody would have also received a shock inside his raft due to proximity and water continuity.
