The signs in the windows of the Russian restaurant change when shown from the inside.
When Kay shoots Jeebs in the head in the jewelry store, the resultant blast sends goop flying everywhere. But in the next scene, the counter and wall behind Jeebs are completely clean.
When Rosenberg leaves his shop, Edgar's "Zap'Em" truck is
visible, reflected in the window. It is parked. The next shot of the street shows Edgar drive by and park in front of Rosenberg's shop.
The address on the back of the MIB business card goes from being below the logo to above it.
The license plate on the LTD changes from centered to the right-hand side during the film.
When looking at the star chart of Orion's Belt, Alnitak can be seen labelled as the middle star. From the northern hemisphere, Alnitak is the leftmost of the three stars of the belt (Alnilam is the middle star, Mintaka is the right hand star).
Kay says the MIB agency fund themselves through "a few patents", one of them being the microwave oven. However the microwave oven was invented in 1946 and is sold commercially since 1955 - before MIB even existed as an agency - making it impossible for them to patent it. Raytheon, established in 1922, owns the patent.
As Zed explains Orion's Belt to Jay at HQ, he rotates the constellation Orion vertically on a screen display and zooms in, showing the Belt's stars (Alnitak, Alnilam and Mintaka) to be in a roughly straight line and of equal brightness. In reality such an "overhead" projection of the Belt would show a long triangle with a very narrow base (Alnilam is about twice as far from Earth as the other two stars), with Mintaka on the right nine times brighter than Alnitak on the left.
When Kay is looking at his lost girlfriend via satellite, the view is
horizontal, as though shot from the ground, rather than "top down", as though shot from space.
The first shot of the film follows a dragonfly flying along a desert highway at night. Dragonflies are not nocturnal and furthermore do not make a buzzing sound when in flight.
When riding in the tunnel, Jay puts on an 8-track and listens to Elvis. Jay quips, "You do know Elvis is dead?" to which Kay replies, "No he isn't, he just went home," implying he is an alien. Earlier Kay reveals the aliens first made contact in 1961 - five years after Elvis Presley made his breakthrough performance in Toast of the Town (1948). However, 1961 is only when they made contact, not necessarily when they first landed.
In the tunnel, Jay falls upside down and appears to have a Caucasian leg. However, the behind-the-scenes featurette shows that Will Smith performed this scene without a stunt double, so this must be a trick of the light.
The opening, which is set in Arizona (saguaro cacti are only found in the Sonora Desert), New York license plates are seen on the cars. However, it is possible that the MIB drove from New York to one of those states as the guy was bringing immigrants over the border.
Kay says, "You should have been here for the Zironion migration of 1968. I guess you were not even alive in 1968."
In MIB: Homens de Preto III (2012), a young Jay is at the moon launch which took place in July 1969, and he clearly is older than 7 months old which would be his minimum age if not born in 1968.
However, Kay is mocking the youthfulness of his new partner.
In MIB: Homens de Preto III (2012), a young Jay is at the moon launch which took place in July 1969, and he clearly is older than 7 months old which would be his minimum age if not born in 1968.
However, Kay is mocking the youthfulness of his new partner.
In the beginning, when Jay chases the alien into the building, he is initially seen running clockwise up the circular ramp, but after the scene cuts away and comes back, he is running counterclockwise.
However, looking at the overhead shot as Jay starts running, it can be seen the first ramp he runs up left to right (clockwise) cuts back sharply, and the floors then all move upward right to left (counterclockwise).
However, looking at the overhead shot as Jay starts running, it can be seen the first ramp he runs up left to right (clockwise) cuts back sharply, and the floors then all move upward right to left (counterclockwise).
In the beginning when Edwards is hanging off the back of a van chasing the guy, as the van turns into a street, it can be seen that there is nobody is in the driver seat, though there is a person sitting in the passenger seat looking back through the window the whole time.
When the bug's spaceship crashes, although it's on fire (coming from sky behind the house) it has no effect on the shadow of the house.
A pedestrian speed-walks past Kay's car window when they are first in the LTD, indicating sped-up film.
At the end, when Jay is fighting the big bug, he throws a rock and strikes the bug in the head. Watching the rock closely, it can be seen to disappear shortly after hitting the ground.
Manny the News Vendor can be seen looking at the camera after getting paid by Kay.
When Edwards moves the table during the "best of the best" test, the scraping sound begins before the table is moved.
When entering MIB headquarters, after spending the night deciding whether or not to join MIB, Edwards says to the security guard, "What's up hoss?" His lips never move.
Right before Kay unplugs the camera in the interrogation he says "Some night huh?" but his mouth does not match.
At 15 minutes when the farmer's wife adds sugar to Edgar the Bug's drink, the word 'Sony' and the serial number and bar code of the Sony prop house is seen on the bottom of the bowl.
When the alien jumps off backward from the roof of the Guggenheim Museum,
a safety cable can clearly be seen on his leg (just before the jump).
When the alien craft crashes, there is a shot of smoke rising, and off to the right side of the scene, men can be seen walking down the hill.
Partial reflection of the camera and its shadow can be seen when the camera follows the bank of lockers during Jay's initiation into the MIB.
When Kay approaches Redgick's car, the shadow of the camera can be seen briefly.
Kay and Jay stop an alien in a car (the alien with the pregnant wife) because the alien is fleeing Manhattan, the area to which his visa restricts him. The alien's car is pointed toward Manhattan.
As Jay chases the alien at the beginning of the movie, the chase starts at Grand Central Terminal. In the next shot, the alien is seen running downtown (the park is on his right) to get to the Guggenheim Museum. The Guggenheim is uptown from Grand Central, and so is Central Park.
When Redgick is stopped with his pregnant wife in New Jersey, the World's Fair-towers in Queens can be seen briefly in the background. Since the World's Fair took place in Queens, it's impossible to see them from New Jersey.
When Agent Kay is looking up his lost love, he types "Truro", then zooms in on Cape Cod. As he closes in, he misses Truro on the map by about 50 miles' drive (the town/village he zooms to is actually closer to Forestdale or Wakeby). Also, the suburban grass lawn is atypical for Truro. Homes are mostly surrounded by pine needles, brush and dunes.
When the recruits are meeting to be tested an Army Lt. raises his hand and says he's an Army 2nd Lt. Except he has the silver bar of a 1st Lt.
As the camera pans into the morgue the corpse on the fridge tray has a neck pulse.
When Zed shows Jay the screen diagram of Orion's Belt at headquarters, the three stars are labeled in reverse of their true order, and Alnilam is misspelled as Alinlam.
When Kay wipes the memories of the cops on the Mexican border, he says the neuralyzer will isolate the 'electronic' impulses in their brains, when actually it's 'electrical' impulses.
In the shooting test sequence, while discussing Tiffany with Zed, J is gesturing with the hand holding a loaded gun, which points all over the place at various times. Anyone with basic gun safety knowledge will be much more careful about which direction the gun is pointed. A police officer should definitely know better.