On the Alba Varden, Riggs empties a full clip into a crewmember, calling out the names of police officers who've died. A bullet wound appears on the chest of the crewman for each name but with his final shot, delivered at point blank range, the crewman's chest is clean.
The female detective calls Riggs to inform him of Murtaugh's disappearance, and identifies herself as "Collins". However, in the rest of the film (and the end credits), she is identified as Megan Shapiro and Collins is the detective played by Grand L. Bush, who in fact is Detective Boyette from the first film.
When Riggs and Murtaugh are leaving the captain's office after being assigned to protect Leo Getz, the writing on the office door changes from "Capt. E. Murphy" to "Capt. L. Murphy", between shots.
When Riggs is escaping from the straitjacket underwater he purposely dislocates his left shoulder. When he gets back on dry land he slams his right shoulder against a car to put it back into place.
When Arjen shows Murtaugh's file to Pieter, the DOB states 5-15-45, which would make Murtaugh 44 at the time the film was released. However, Murtaugh was celebrating his 50th birthday in the first film in '86, so assuming the release date is "film canon", his DOB should be in 1936, making him
53. Murtaugh also states that he will retire at 52, which can't possibly make him 53 years old in this movie. The first film was also set during Christmas, therefore his birthday should be in December.
The MythBusters (2003) duplicated the toilet bomb and showed that, by freezing the battery with liquid nitrogen, the explosion would have been delayed by about 15 minutes.
Arjen Rudd claims throughout the movie that he has diplomatic immunity. Rudd works for a consulate - not an embassy - and therefore would have consular immunity; this is similar to, but weaker than, diplomatic immunity (e.g., it generally does not provide immunity from arrest/prosecution).
People with diplomatic immunity do not have automatic carte-blanche to commit any crime without punishment. If a person with diplomatic immunity commits a crime, law enforcement has to contact the host country, then the diplomat either has his immunity revoked for trial or gets deported back to his/her own country to face consequences there. Arjen Rudd would certainly face (at best) life in prison after shooting a cop in cold blood: the South African government would give him up rather than face an international incident.
In the scene in which Riggs and Murtaugh drive the car out of shipping container, it is highly unlikely that the vehicle would have had enough power to push through multiple pallets of money, easily weighing at least 500 pounds each, *and* break though the heavy, locked, steel doors of the cargo container, from a standing position. This would require the vehicle to have a "running start", and it simply didn't have the room inside the container.
After the bomb goes off in Murtaugh's bathroom, the toilet , which is where the bomb was, can be seen hitting his car outside. A bomb blast would have shattered the toilet, since it is made of porcelain.
When Murtaugh is showing Riggs the new addition to his home, the contractor fires his pneumatic nail gun. In all scenes, it can clearly be seen that there is no air hose attached to the gun, seemingly making it impossible for it to work. However, some nail guns are powered by batteries, CO2 gas, or even blank cartridges. The nail gun used doesn't appear to have the 'air hose' connection.
In the opening pursuit scene, the police unit call signs are given as 20W15 (Riggs & Murtaugh) & 20W12. LAPD unit call signs consist of the Division number, then a unit type letter (W to indicate detectives), then the specific unit or patrol area number. LAPD Division 20 is Olympic Division, which came into existence in 2009, 20 years after the movie.
The "Liquid Nitrogen" brought in by the bomb squad bring in during the bathroom bomb sequence is just dry ice in water in a Pyrex measuring cup. Real liquid nitrogen has to be kept in a special container to remain a liquid so if they tried pouring it in a room temp open air container it would revert to gas almost instantly and be useless.
When the surfboard is flying through the windshield of the tow-truck, you can see a black dropcloth in the driver's window, which is there to hide the fact that there is no driver.
On the Alba Varden, when Riggs is shooting the bad guy in the beige shirt while saying the names of all of the people who have been killed, bloodstains appear on the bad guy's shirt; however when Riggs gets close to the guy, there are no bloodstains.
When Riggs pulls Murtaugh out of the toilet and into the bathtub just before the toilet explodes, if you look extremely carefully, you can see Murtaugh is wearing dark pink briefs, even though he should have been naked from the waist down for obvious reasons.
When the coins spill out of the flipped over car's truck, the coins are clearly blank with no image pressed into them.
After the car is driven out of the cargo container and lands in the water with all the money (at the end of the film) As Riggs and Murtaugh run to the end of the hanging container armed with machine pistols, there are already 2 conveniently tied off hanging ropes for our heroes to repel down to the ship.
When Riggs and Murtaugh go into the cargo container, in order to see, Riggs turns on the car headlights which is facing the pallets of money. When the container doors explode open, the car has somehow turned around so the front is now facing away from the pallets towards the container doors.
Riggs' hair changes lengths several times throughout the film.
Obvious manikin replacing Shapiro in the pool scene.
When Riggs and Murtaugh discover that most of the cargo inside the container is money, Murtaugh notes that "...they're all $1,000.00 bills." Presuming that the movie is set in 1989, the year of its release (see trivia), all denominations of US currency above $100.00 had been withdrawn from circulation for twenty years. Large denomination bills are now mostly in the hands of collectors and dealers. The huge quantity of such large bills would immediately draw suspicion no matter what their source. Part of the reason for the withdrawal was because the large denominations were not widely used enough; other motives include making it more difficult for criminal traffic in large amounts of currency, just the sort of situation depicted in the film. In 1989, there were approximately 220,000 $1,000 bills still being used, considerably fewer than the number of bills on the pallets.
The commercial with Murtaugh's daughter premiers during And All Through the House (1989). Tales from the Crypt was on HBO without commercials and didn't become syndicated until 1994.
Immediately before the first viewing of Rianne's commercial, when Carrie and the rest of the Murtaugh family are admonishing Roger for eating tuna, Carrie mouths the "Daddy killed Flipper" twice, though in the audio, she says, "you can't eat tuna" the first time, and "Daddy killed Flipper" second.
When Riggs is climbing out the water after removing the straight-jacket, you can see the lights shining from under the water, used to make it easier or possible to see Riggs and his "girlfriend" when they were under the water.
The camera is reflected in the window of Riggs' truck when he drives off after blocking in the car of the South African diplomat.
At the 9856 "house on stilts" Leo identifies, when Riggs and Murtaugh are walking past the front of the house, several crew members can be seen in a reflection behind them.
Six minutes in the shot from the hero car shows the entire camera crew, overhead crane, public spectators and medic/Ambulance are shown in vivid detail standing around. May only be on certain cuts of the movie.
On the Alba Varden, just before Riggs gets knifed in the leg, a shadow of the camera, as it moves backwards, can be seen on the large orange container next to Riggs on the right of screen.
When Vorstedt reveals to Riggs that he was the one who mistakenly killed his wife, the whole subplot makes very little sense. If the "contract" was on Riggs' life, it's unlikely that Vorstedt would just drop it after the mistake and fail to proceed to kill Riggs himself. It's also unlikely for a character like Riggs to give up a hot case even after a grave loss. Even if he was pulled off the case, someone else in the PD would have picked it up after him.
After Riggs has shot up Arjen's aquarium, and Rika meets him in the hallway afterwards, there is a very slight boom shadow that comes into shot on the back wall near the flag (Wide-Screen Edition).
Obviously, the subplot involving Leo Getz (Joe Pesci) was about protection for his money laundering against the South Africans. In spite of this, he enters the South African counsulate with Murtaugh, offering a diversion for Riggs to enter. This is making a spectacle of himself in front of the very people he means to avoid.
When Peter shown Arjen Murtaugh's file, it says his birthday is May 15. However, in the first Lethal Weapon, Murtaugh was celebrating his birthday around Christmas time.
When Riggs is outside the South African consulate, holding his sign, the word 'apartheid' is spelled wrong. The sign Riggs is holding says, 'End Aparthied Now."
When Riggs is talking to Trish about the night his wife died, his Australian accent is very evident. In the supermarket, he pronounces "horsing around" with the same accent.
When Pieter explains to Riggs that he murdered his wife, he says that they put a contract out on him, and then that he handled it himself. He wouldn't have to use a contract killer if he intended to just do it himself.