Continuity mistake: At the start of the movie when Goodspeed and Marvin Isherwood are in the FBI lab trying to diffuse the gas bomb, when Goodspeed first walked into the chamber he stated his name, etc. he said that the time was 9:00am. However in the background you can see a clock that says the time is around 4:15. (00:08:35)
Continuity mistake: While in the chamber Isherwood shows his glove and says it is eating them. We see him looking through his helmet at the glove and it is covered in foam, however in the next shot from the outside, there is no foam at all. (00:09:55)
Continuity mistake: When Nicholas points a gun at Connery on the balcony, he pulls the gun's hammer back. In the next shot it's not pulled back anymore. (00:39:45)
Continuity mistake: During the Hummer chase scene, after the Hummer smashes into the truck with all the water jugs, you can see from a shot inside the Hummer that the windshield is cracked. For the rest of the chase, it isn't. (00:45:28)
Continuity mistake: Nick Cage is chasing Mason in the yellow Ferrari. The windshield breaks at least twice, but is perfect in the next shot. (00:45:55)
Continuity mistake: When Goodspeed is on the roof of the lighthouse with the last pearl configuration of poison gas, one of the 'pearls' drops off the bottom. As he chases it across the roof, from the front shot he has his right hand outstretched. As he dives to grab at it, the shot switches to the side and it is his left hand that grabs the 'pearl'. The shot then immediately switches to a close up of his face and you can again see his right arm outstretched. (01:54:30)
Continuity mistake: When Hummel sends patrols in search of the SEAL Team, the Marine with the messed up hair-cut(the spanish guy with the "bun" on his head) stays behind and is watching the monitors. There are shots of him watching the monitors and saying "something's not right." Yet there are also shots of the Marines on the patrols, and he is one of them. The it cuts back to the monitor and he is the one that alerts the Marines the shower room has been breached.
Continuity mistake: In the car chase scene, Mason is driving the stolen Hummer and he hits a meter maid truck sending it flying into a telephone pole and blowing it up. They slow down the film a little here and show us this hit from several different angles including from above. When they slow down the film you can see that the Hummer is turned sideways in the impact but in the next frame it drives off as if it had just tapped the meter truck and not slammed into it as shown.
Continuity mistake: As the seal team are about to enter the shower room, we see them cutting the sensor beam using two mirrors. In the next shot we see the seal removing both of the mirrors from the drain ready for incursion. In the shot in which they pull back the drain, one of the mirrors is still there.
Continuity mistake: In the chase scene, Cage is in a real Ferrari F-355 at some points, but the car switches to a replica 'kit car' in various scenes. When it is crushed, you can see the fibreglass kit car body pop off to reveal the Pontiac Fiero guts. I heard our friends from Maranello were not impressed.
Continuity mistake: During the movie when Mason is talking with his daughter in the park, his tie in one cut is tied differently then in another cut of the same scene. Look closely at the stripes.
Continuity mistake: When Nicholas Cage steals the motorcycle and is talking on the cellphone, the camera shows a close up. For a split second it shows the front tyre of the bike, and if you look closely the tyre is not turning.
Continuity mistake: During the chase scene, just before the Ferrari is destroyed by the trolley, you see Cage dive out of the car and a rear view of the trolley hitting the car. In this shot, you see the complete rear end of the Ferrari, with a blue pickup next to it. In the very next shot, the Ferrari is getting sandwiched between the trolley and the pickup.
Continuity mistake: Towards the end of the movie when Ed Harris gets shot watch him fall. He lands on a mat then a second later you see him being dragged by Nicolas Cage and the mat is gone.
Continuity mistake: In the scene where Nicholas Cage and Sean Connery are held prisoners in the cells in Alcatraz, Connery has made a rope and swings it for the first time, and the handle for one cell is brought down, opening the door of the cell beside Connery. However, when he tries for the second time and gets the correct handle, the handle used previously is back in its place, and not horizontal as it should have been.
Continuity mistake: When Goodspeed stabs himself in the heart with the syringe at the end, we see an aerial view of him lying on the ground, gasping. When he gets up to ignite the flares, the syringe is gone. You can't see it when he lands on his knees, and we don't see him pull it out.
Continuity mistake: The number of jets flying towards The Rock were 6, there's only 4 jetplanes when they approach the Golden Gate bridge and the number of jets flying under the bridge is 5.
Continuity mistake: As Mason escapes from the hotel, we see him running down the escalators to the kitchen. On his way down, he pushed over two waiters who fall, the waiter on our left falls onto his back on the close up shot, but as the shot changes to the wide shot we see him falling again onto his front.
Continuity mistake: In addition to the incorrect time for the opening sequence in the chamber, in the initial close-up shot of Cage you can see a clock on the right. The two hands are both near the seven, so about twenty-to seven then. In the wideshot of him, the clock shows the time as quarter-to instead. The original twenty-to time is used for the rest of the scene.
Continuity mistake: When the Marines are at the Naval Weapons Depot, one of them drops the cylinder carrying the VX Poison Gas. They run out, and when the guy drops the canister (containing the cylinder of gas), the cylinder with the gas has disappeared.
Chosen answer: Alcatraz is small enough and out in the middle of the bay that any lookout in a high point could see and hear a chopper, no matter where it approached from. The idea of the decoys was to split any enemy fire received. The whole insertion of SEALS was absurd, in a real situation like that, the SEALS would have been inserted by submarine or used dive motors to pull themselves to the island.
Grumpy Scot