Character mistake: When Ripley interfaces with Mother for the first time and sees the special order, an instruction reads as "Insure return of organism" rather than "Ensure return."
Visible crew/equipment: You can see the string that pulls Bubba off the bike when Max shoots him. (01:19:41)
Continuity mistake: After Ajax is arrested Swan goes to the station with "tough chick", the first time you see the train platform it's empty but a few seconds later a man has appeared from nowhere, then a policeman sees Swan and chases him and the man has once again vanished. (00:55:25)
Factual error: Although it's already been mentioned that the scene of the shuttle being stolen from the back of the 747 is impossible because the shuttle wouldn't be fueled while being transported, it should also be noted that even if the shuttle was fueled, it would still be just as impossible. During the getaway, the thieves ignited the shuttle's three main engines to get free of the 747 and escape. The thing is, the shuttle's main engines are fueled entirely by the large external tank the shuttle and the solid fuel boosters are attached to during liftoff, and once the tank is jettisoned, these engines cannot be used. The only engines the shuttle's internal fuel feeds are the reaction control thrusters and the Orbital Maneuvering System (which are the two smaller engines located in the bulges just above the main engines). Both the RCS thrusters and OMS engines are almost totally useless within the atmosphere, so even if the thieves managed to get the shuttle free of the 747, they could only get it as far as it would glide unpowered. In fact, they could probably get it further if it wasn't fueled. It should be noted that this is not a fictional, futuristic spacecraft. It's a bog standard shuttle, stolen from NASA, on the back of the modified 747 used by them to transport the orbiter from its landing site to Cape Canaveral.
Continuity mistake: When the stairs are first shown, there's carpet up the middle of the stairs. At the end when they flee the house it's gone.
Factual error: In the opening scene that shows San Francisco scenery there is a shot of a large TV tower called Sutro Tower. The film takes place in 1960 and Sutro Tower wasn't built until 1973.
Factual error: After the turbine trip, Godell says that the reactor water level was "almost up to the steam lines." The fictional Ventana nuclear plant is described as being a pressurized reactor plant and could not possibly have such a problem.
Plot hole: When Jack The Ripper checks his watch before confronting H.G. Wells and demanding the key, the hands point to 8:50, the ensuing chase to the museum and demise of the Ripper may have used up a half hour or so, yet the time on the wall clock indicates that it is midnight.
Suggested correction: Movie time and real time don't match, so 3 hours has passed without all 3 hours being shown. The fact that the clock now shows midnight is meant to explain this fact without the need for subtitles to reveal the time.
Visible crew/equipment: Young vampire Danny floats away from the window after being confronted with a crucifix. The effect is quickly ruined when the boom he is sitting on can be seen moving him for 8 seconds. (01:43:40)
Continuity mistake: During the time when Vince and Sheldon are on the highway, in the cab fleeing the bad guys in Tijada , the same cars can be seen over and over again between shots.
Plot hole: In one scene saboteurs rig the Concorde's cargo door to automatically open suddenly in flight, on the principle that the rapid decompression will cripple the airplane & cause it to crash. At the critical time the door does start to open, but jams and only opens very slightly. Minutes go by, with the ajar hatch allowing air to freely pass through. Then, suddenly, the door unjams, and the compartment is shown losing air pressure dangerously fast. Problem is, that since the door had been cracked open for several minutes, the air pressure would surely have gotten to equilibrium by that time. (01:32:45 - 01:36:30)
Continuity mistake: When Watson is conned by the prostitute who says she knows Mary Kelly, she lures him into a closed alley. After Watson has called the police and subdued the attacker, 2 constables arrive and arrest Watson, but as they all leave, a third constable comes from behind the camera. Either he magically appeared, or he walked through the wall behind.
Continuity mistake: When Amanda rushes to get onto the bus to the train station, the door being opened is at the front LEFT of the bus (as viewed from the back). On arrival at the station (5 scenes later), the door opens at the front RIGHT of the bus (as viewed from the back), and in the second camera shot, the driver of the bus can be clearly seen sitting where the door Amanda used to board the bus would be, with no door there.
Factual error: When Mission Control talks with Challenger 2, the Spacecraft's camera feeds of the Crew are displayed up on two wall-sized TV screens. Between them is the familiar Mercator map of Earth with the ground track of a low-orbiting satellite superimposed. Challenger is nowhere near low orbit: it's out past Mars, in the Asteroid Belt. The middle screen would have a schematic of the ship's interplanetary path.
Factual error: Harry goes to the synagogue, to go through a register his grandfather's records. But he is holding the Talmud and not a register, which is entirely and Hebrew, and he's looking at it upside down. (01:05:00 - 01:06:00)
Continuity mistake: The babysitter answers one of the early calls saying "Robert, I don't think this is very funny." The pencil and papers have completely changed position on the table. (00:07:30)
Revealing mistake: When the purser's safe falls through the ceiling, the ceiling metal is far too thin. Bearing in mind also, that the on the other side of the ceiling metal is supposed to be the floor of the next deck up, and that too is a thin flimsy metal, that doesn't even appear that it could support any kind of weight.