Continuity mistake: When Keanu and Jeff are on their way to the building at the start of the film, their car flies over a hill and lands back on the road. The right hand front wheel takes a really nasty knock as it lands and looks ready to come off, and yet in the next shot they arrive safely with no apparent difficulty driving the car.David Mercier
Continuity mistake: When the LAPD are making the money drop, one shot from Dennis Hopper's apartment shows a businessman walking past the garbage can with a silver briefcase (just as the garbage man comes), and the same man with the silver briefcase walks past about a minute later in another shot when Keanu Reeves is running towards the bin.
Continuity mistake: After the bus driver looks at the note "Bomb on Bus" he starts decreasing speed. So Keanu puts the Jaguar beside the bus and tells the bus driver to open the door for him to tell the driver to go at a speed of 50 miles per hour. Just before this you can see a camera shot in which the door is already open. This mistake is easily seen if you watch it in slow motion.
Continuity mistake: At the start when Jack is trying to get on the runaway bus, he is seen passing the guy in the convertible Jaguar on the freeway entrance-ramp. He continues to overtake lines of stationary traffic in order to catch the bus, and then pulls alongside it. In the next shot he commandeers the Jaguar so he can use it to get onto the bus; however the Jaguar should still be waiting in the queues some way behind. (00:32:55 - 00:35:00)
Continuity mistake: When Howard Payne calls Jack in the bus and is saying he wants his money, etc, at the start of the next scene the bus can be seen with not only its front doors open, but the back doors are also open with a guy standing on the step in the doorway, even though the back doors haven't been opened yet. This shot is actually cut from the following scene, when Jack gets off the bus, the young guy from the bus stands in the doorway looking out at Jack leaving. (01:07:55)The-Immortal
Continuity mistake: At the beginning of the movie after Jack has hooked up the crane from outside to the lift, there is a shot of the crane outside, and the line going through the vent. If you look closely there is a pipe in front of the vent, yet when the crane goes through the vent, the pipe has vanished. (00:14:20)The-Immortal
Continuity mistake: At the end of the film, the train flies off the track, through a wood-framed tunnel under construction, and then onto a city street. During the credits, as the shot is pulled back, there is no destroyed wood-framed tunnel. In fact, traffic is flowing normally in the background.
Continuity mistake: When Howard Payne is in the elevator, he hears Jack and Harry doing something from above, and he reaches for his bomb trigger. In slow motion when he's picking it up, it has two buttons on it, yet when Howard pushes one of the buttons, the device now has three. (00:13:00)The-Immortal
Continuity mistake: When Jack is chasing the bus on the freeway in the Jaguar, an overhead shot is shown of the bus with three cars around it, but in the next shot of the traffic, the road is full of traffic which is surrounding the bus, which is highlighted by Jack having to swerve around the cars.
Continuity mistake: When Dennis Hopper's shooting the shotgun through the lift roof, the number of holes doesn't match the number of blasts. He shoots once and a hole appears. We then see a close up of him and he shoots twice more, but when we cut to the ceiling after the third shot overall, there are only two holes in it. Doesn't seem likely he'd miss the roof at a range of 2 feet. (00:18:55)Jon Sandys
Continuity mistake: Near the end of the film when Keanu Reeves and Dennis Hopper are wrestling on top of the subway, if you watch Keanu's left wrist you notice he is wearing a watch. Yet throughout the scene it is obvious that the stunt double has no watch, because in the extreme action scenes, there are no signs of it anywhere on his wrist.