Goofs

There is no ambulance in the truck when the terrorists first arrive, but Theo drives an ambulance out of the truck near the end of the movie (error acknowledged by filmmakers).

The FBI sends two helicopters to Nakatomi, but just before the John-on-the-roof sequences, the second helicopter disappears and is never seen again.

John McClane starts off with a clean white tank top shirt that becomes dirty and bloody. Then suddenly it is uniformly brown.

Takagi was born in Kyoto in 1937, yet a computer readout displays his military service assigned to the aircraft carrier Akagi in July 1940. It would be impossible for him to serve the Imperial Japanese Navy at the age of three.

The orchestra disappears. They are playing when McClane is driving to to the Nakatomi Building, they are playing after he arrives and they are again playing when the terrorists burst into the party. However when the hostages are rounded up and later when they are herded up to the roof the orchestra members are nowhere to be seen.

Several times during transmissions with the two-way radios, characters interrupt each other, which would be impossible given the type of radios they were using.

When McClain calls the Emergency Distapch he uses a radio yet the Dispatch operator sees a telephone number on the computer screen.

When McClane drops the monitor with the C4 down the elevator shaft, he has time to jump away from the door as the explosion rises. The gases from C4 actually expand faster than the speed of sound, so his face would have been melted off.

When John sets off the fire alarm to alert the authorities Hans tells one of his men to call the fire department and report it as a false alarm. The fire trucks and emergency vehicles are called off and turn around without ever reaching the building. This is not the usual procedure when a fire alarm is sent via an alarm system, fire departments are required to verify for themselves that there is no fire to prevent the possibility of arson by a disgruntled employee. Even if they are called with a code or speak personally to a building owner, the fire department must verify independently that there is no fire.

The FBi cannot simply take over the hostage situation from the LAPD, nor would any of the LAPD brass allow it, especially not to a mere two FBI agents (Johnson and Johnson). At best, they would try to work together, and there is no way the LAPD would allow the Johnsons the freedom to fly a helicopter over the building and take shots at anyone on the roof.

Early in the film, shortly after the terrorists have launched their assault, McClane glances out a window and sees a woman in the building across the street. However, previous and subsequent long shots of the building he's in show that there are no other buildings close by.

At the start of the scene when Hans is threatening Takagi, he is seen removing a noise suppressor (colloquially, a "silencer") from the end of the barrel. However, as the pistol he is holding (a Heckler & Koch P7M13) does not have a barrel long enough to thread a suppressor on on the outside, the crew threaded the inside of the barrel for the production. As Hans removes the suppressor, you can see that the screw used to mount the suppressor would completely block the barrel, rending the pistol useless.

When Hans is holding onto Holly's watch out of the window and then falls, he is shot in slow motion but the paper that is falling in the background is moving at normal speed.

When jumping off the roof at Nakatomi Plaza just before it explodes, you can clearly see John McClane's "rubber shoes" that were used to protect his feet. While the people are being held hostage, he is supposed to be barefoot. His support wire is also visible in addition to the fire hose.

Obvious stunt double for McClane (missing a tattoo on the shoulder) during the fight with Karl.

Johns holster disappears after entering the stairway when the terrorists first arrive. unwise since it carries his spare mags (which can't be seen on him) and if the holster was found it most likely alert the terrorists of an armed man in the building.

When McClain kills the first terrorist, he tries to take his shoes but is not able to as they are too small. McClain then kills several more terrorists but is never seen checking their shoes.

The terrorists launch an explosive projectile twice at the police tank and the same window bursts twice.

When Argyle places the cassette into the limo's tape deck and turns the volume up, he uses the 'bass' knob instead of the volume knob and the volume of the music increases.

When Hans says Bill Clay, his false name to John McClane while they are on the 33rd floor, the camera zooms in on the name directory and we can see the name Aster and under FL the number 39 but the Nakatomi building has only 35 floors.

In the scene when Hans sees the news clip of the McClane children on TV he then picks up the portrait of McClane and his family and knows right away the Holly is the wife of McClane u would think Hans would have viewed almost everything in the office from the beginning and known her true identity..

When John McLane finds Hans Gruber up on the roof of the Nakatomi Plaza, Gruber says "Please God NO!.. You're one of them hosta", when he mistakenly starts to say "hostages" instead of "terrorists".

The audio is then clipped, and Gruber repeats "You're one of them"

When Takagi speaks to the employees at the party they erupt in loud applause. Looking at the employees, none are clapping their hands.

When the swat team is trying to enter the building and they fail to pick the lock, a swat team member clearly lights a cutting torch to burn the lock. A few scenes later you can clearly hear a grinding sound indicating a drill or grinder is being used to try to break the lock.

When John is first chased by a terrorist, up on the floor still under construction, he turns on and off a radial arm saw. The very distinct sound of the blade running against either a kerf in the fence or a kerf in the table can be heard. However, when the terrorist finds the saw, it can be clearly seen that the blade is running free.

When the terrorist car first pulls up to the Nakatomi Plaza, the noise from the brakes is not consistent with the movement of the vehicle.

At the end of the movie we see the building exploding from a distance. The sound of the explosion is at the same time the explosion happens but since light travels faster than sound, it should have been at least a few seconds between the explosion and the sound.

After the 911 call gets cancelled, the guard goes to floor 32 where John is. When the guard turns on the lights, the camera crew is reflected in the window.

As John is fighting Karl toward the end of the movie, Karl's harness is clearly visible as he is dragged across the room by the chains which are supposedly round his neck.

When Hans crashes through the window after being shot, and drags Holly with him, the line attaching Holly to the ceiling is visible in the exterior shots looking in.

In the shots that we see of John McClane when he asks the hostages where his wife has been taken to by the terrorists, you can see the pyrotechnic charges taped to the roof that are about to be used. When the helicopter swings overhead and a soldier uses his machine gun, you can see the charges detonating and the fact that they are charges being used to simulate M-60 bullets hitting the roof.

After John hangs Karl in the roof equipment space, in the next shot where he reaches for his gun on the floor and checks to be sure it's loaded, either Alexander Godunov or his stunt double is visible standing atop the stairs behind John, in costume as Karl, in black shirt and pants, watching the scene being filmed.

The "terrorists" plan to get the FBI to cut the power to Nakatomi Plaza so the lock to the vault will open and they can steal the bearer bonds it contains. Any electric device of this criticality would be connected to a UPS - Uninterruptible Power Supply - so even if the utility power were cut it would continue to function.

After McClane kills Tony on the stairs, it was unwise of McClane to confirm a rogue element by sending Tony's body down in the elevator and alerting the rest of the terrorists, he should have just hidden Tony's body and used his kit.

The terrorists maybe would have come to investigate Tony's whereabouts but not in numbers, expecting someone with a machine gun, ho, ho, ho.

Karl and Tony disable the entire phone system, while Tony sets up a feedback loop to keep the intrusion from being sent out as a service outage or tampering with the Telco Equipment additionally to prevent Alarms from being triggered and sent to the 911 Center. 14 minutes later, McClane pulls a fire alarm station, which sent the alarm to 911, despite all the phone lines being cut and looped back.

After Hans shoots out the glass and John cuts up his feet, making them bloody. Hans could have simply followed Johns bloody footprints and caught up to him and shot him dead. It doesn't make any sense, that he doesn't.

When Sargeant Al Powell talks to the other Sergeant about not liking the fact that the 2 helicopters are on their way with the FBI agents inside, they are shown looking at the 2 helicopters coming toward Nakatomi Plaza. The 2 helicopters are within sight yet it shows them flying around other buildings and taking way too much time necessary to reach Nakatomi Plaza.

Just after we are first introduced to Johnson and Johnson, Hans is seen walking on the top floor in, looking up and shining his flashlight. In the Forward Tracking Shot, just before he climbs the wall, the shadow of the boom mic is visible just above his shadow on the far right of the screen in the widescreen version of the film.

When the terrorists are first walking in as a group looking very serious and sinister, the one on the far left is on a collision course with the wall! The camera cuts away just before he walks into it.

When the SWAT team is trying to break into the front door of the tower they first try picking the lock to no avail. Then we see a SWAT team member carrying a metal cutting torch attempting to cut through the lock. The SWAT team would have just broken the glass to get in and not waste time using a metal cutting torch to cut the door lock. The glass is obviously breakable as shown in the same scene when the terrorists fire upon the SWAT team.

Holly's maiden name is correctly spelled 'Gennaro' in the computer system, but, when John taps it on the screen, it changes to 'Gennero.' It is also misspelled as 'Gennero' on her office door.

Takagi mentions that any computer information Gruber gets would be changed "when they wake up in Tokyo in the morning." Japan is 17 hours ahead of Pacific Standard Time, so early evening in California corresponds to roughly midday in Tokyo. The workers wouldn't need to "wake up" at all because they'd already be at the office.

When Theo updates Hans on the police activity, he reports that "the four assholes [are] coming in the rear in standard two-by-two cover formation." The SWAT team members are not in '2x2 cover,' they're all running together single file (more or less).