Continuity mistake: Right before they rob the police car, a Boeing 747 (four engines) is seen in shots of the plane coming into land. When the plane is shown from behind, it is a Boeing 767, with only two engines and fewer main landing gears. (00:30:10)
Continuity mistake: There's an electrical outlet on the wall below the window (aligned with the window shade's loop) in Sid's room near the Megadork poster, but when Sid throws Woody to the floor and raises the shade (before he scorches Woody's forehead with the magnifying glass), that outlet has vanished.
Factual error: Fitch, who professes qualifications in biology, genetics and biochemistry, says that they made Sil female because she's a natural predator and so she'd be more docile. He should retake his finals. In every single species of predator on earth - every single one - the females are the hunters, aggressors and killers. The males may be socially dominant but they are the 'docile' ones. There are no exceptions - and no human DNA was used to create Sil - they used synthetic DNA based on the instructions transmitted to them.
Visible crew/equipment: After Josh tells Cher she's such a brat, at the start of the next shot which is the first close-up of Cher during the driver's test, just as she says, "I had an overwhelming sense of ickiness, even though I apologized to Lucy," the top of a crewmember's head, with his short wavy hair blowing in the wind, is reflected at the bottom of the Jeep's windshield, directly in front of Cher and the steering wheel. (01:11:55)
Revealing mistake: Near the end when Ace gets into his Cadillac, in the first shot facing the front of the car, there is a protective glass in front of Ace (the same width as the windshield) with the dashboard in between that glass and the windshield. Note the vertical edge of the glass is visible at the right side, and the rearview mirror's sticker on the windshield casts a shadow onto the second glass. During the stunt, the flames on the dashboard are between the glass shield and the windshield, keeping the actor safe from harm. (02:46:05)
Revealing mistake: On Billy's first day of school when he is outside waiting for the bus and it just passes him you hear the noise of kids on a bus, but when it passes no one is in it.
Other mistake: When Somerset goes back to the man's house alone, he cuts a sticker on the door with his switch-blade to get in. The first error is the sticker is on the inside and it says "Keep Out." The best part about it is the door opens inward. How did they put the sticker on the inside and then exit? (00:20:45)
Revealing mistake: The kid in the wheelchair is playing a Game Gear with no game in it.
Factual error: No electricity, yet the washer is running.
Continuity mistake: When the two female characters enter the fancy hotel room, they make a point to say they will only be there for a couple of minutes. It is daylight when they go in. The visit is cut short (the one that's supposed to be a few minutes long) because of a gun battle in which one of the women dies and the other escapes. The escaped one gets out through the roof into an evening's sky. There's still light visible, but for a visit that lasts all of 4 minutes, it's far too quick a change. (00:23:00)
Continuity mistake: There is a scene where everyone is dancing. It's towards the end but not at the very end. One of the employees of the record store takes his shirt off. Then the camera cuts back and you see the entire group of people dancing. If you look at him he has his shirt back on. Then a couple of shots later he has it back off again.
Continuity mistake: When Johnny Cage is fighting Scorpion, and he does his human spear, Johnny runs until he stops at the tree. The spear then catches up, and becomes wrapped around the tree in front of Johnny. When the camera changes view, the spear is just leaning on the tree. The camera changes view again and the spear is wrapped around the tree again. When Scorpion pulls the spear back, it goes straight back, and doesn't unwind around the tree.
Continuity mistake: When the white boy is standing outside the car talking to the gangbanger inside the car, the gangster's sunglasses disappear depending on the camera angle.
Factual error: When Zach and Nomi are talking on stage after Nomi's disastrous experience at the boat convention, Zach places a call to Phil Newkirk. There are several problems with the call: the cell phone doesn't appear to be on (he raises the antenna at the beginning and end of the call, but he never presses an "on" or "off" button); Zach doesn't punch in enough numbers for the call to appear legitimate (too many numbers for speed dial, but too few for a local seven-digit phone number [also, since he was using a cell phone it's unlikely that he dialed a hotel extension number]); and the pauses between his words and Phil's response on the other end of the line are too short to be believable.
Factual error: When McClane and Zeus take the little hatchback from the bank location, they run up the ramp by the Brooklyn Bridge and McClane looks to see the dump trucks aren't on the bridge. Zeus then spots them on FDR Drive and they speed off down the ramp to FDR Drive. The ramp they were on doesn't connect to the ramp they took to give chase. It only heads towards City Hall or over the bridge. They'd have to take the Civic Center ramp, do a u-turn under the Brooklyn Bridge approach then head back up the ramp to FDR Drive.
Visible crew/equipment: During the "full attack" at the start of the Battle of Stirling Bridge, Wallace repeatedly shouts, "Hold," and in the wideshot right before Wallace finally shouts, "Now!" as the horses gallop towards the right side of the screen, we can see a white car at the left side of the screen. Viewed widescreen version. (01:27:15)