The filming of the alley scene was very troublesome for the filmmakers due to it being filmed in a very rough neighborhood. The alley was littered with garbage, most of which was used in the film, and plagued with large rats. Local residents angered by the noise created by the film crew would throw bottles and paper bags filled with feces from windows at the crew in the alley below. Worst of all, the film crew found a dead body hidden amongst the garbage.
Putting the Alien (1979) skull on the trophy case on the Predator ship was the idea of Stephen Hopkins' as a way of showing off all the different species and creatures that the Predators have hunted and killed. It was also a nod to the Dark Horse Aliens vs Predator comics which were quite popular at the time. Since Fox had owned the Alien film series, it was easy to obtain the rights to use the Alien head in the film. This excelled popularity of the Aliens vs. Predator series crossover throughout the 1990s, and was promptly followed by more comic books, novels, video games, toys, and eventually movies.
The plot underwent a few changes in its earliest stages. Gary Busey's character, Keyes, was actually intended to be Dutch, Arnold Schwarzenegger's character from the first film. Schwarzenegger was very outspoken against the sequel's concept, feeling that taking it into the city was a bad idea, and declined the role.
Elpidia Carrillo, who played Anna in the first Predator film, has her name listed in the sequel's credits yet doesn't seem to appear in the actual film. Look carefully during the scene inside Peter Keyes' mobile headquarters and you will spot her. When Keyes (Gary Busey) describes how the creature activated a self-destruct device in Predator (1987), you can briefly spot Anna on one of the video screens. Carrillo filmed a debriefing scene in which she talks to the camera and describes the events of the first film, but it was cut from the sequel.
With more time than the original Predator (1987), Stan Winston, Stephen Hopkins and Lawrence G. Paull came up with ideas and designs with more exotic weapons (the retractable spear, the detachable pincers, the Smart Disc, the net, etc.) for the Predator to use to differentiate this film from the previous one.
Rubén Blades was giving a live TV interview to Good Morning America (1975) from the set of this movie. During the interview, director Stephen Hopkins walked on camera and ordered Blades back to work very loudly. The incident was so embarrassing, Blades and Hopkins did another interview days later to apologize.
When the Predator gets shot in the slaughterhouse sequence by Danny Glover, Kevin Peter Hall had blood packets filled with the luminescent fluid from a "glow stick" mixed with K-Y jelly attached to his body to create the glowing, green blood.
According to writers Jim Thomas and John Thomas, a Predator sequel had not been planned and they had to wait to see how successful the Predator comic book series would be. After the series was a hit, producer Joel Silver was finally able to convince Fox to make the sequel, which was immediately greenlit.
The original storyline of the film was to have taken place in New York City, but writers Jim Thomas and John Thomas quickly changed it to Los Angeles because of budget concerns. The scene where the Predator raises the skull during the lighting storm was to have taken place atop the Chrysler Building.
The Predator Elder has a scrap of olive drab fabric with a patch on it, on his right forearm. The patch is for the U.S. Army's 2nd Infantry Division. The 2nd Infantry Division was involved in some of the worst fighting of the Korean War, especially during China's winter offensive. If this Predator did kill an American soldier during the Korean War, that would imply that the Predators are not strictly attracted to "heat and conflict." though during the summer Korea is known to Be Hot and Humid
According to Gary Busey in an interview, Keyes and the CIA had been setting up CIA commissioned missions in the jungles on the Predator, which Dutch had been involved in, after the events of Predator (1987), but they had lost Dutch. Which explains why Dutch (Schwarzenegger) didn't appear in the sequel.
The scenes where the Predator attacks the subway were shot on a massive soundstage at Fox. The scenes where the train is actually moving was shot in Oakland, California, with actual subway trains running.
In the original Predator (1987), when the camera pans to the Predator's HUD view, human voices are audible as high-pitched. In Predator 2 (1990), human voices are audible as low-pitched. However, it is also revealed that the Predator has several visors at its disposal, so this may also affect the way it records sounds.
Stephen Hopkins was given the task of directing Predator 2 (1990) after greatly impressing the studio when directing A Nightmare on Elm Street 5: The Dream Child (1989). He had been given just four weeks to shoot and a further four weeks to edit the film. This meant that he had to shoot on one stage while the crew dressed the other, allowing them to shoot almost continually.
The widescreen VHS released in the UK in April 1998 had the very unusual aspect ratio of 2.05:1 despite the fact that the film was intended to be in 1.85:1. This was the only release of the film to be framed in this ratio.
The flintlock pistol thrown to Michael by the other Predator is engraved "Raphael Adolini 1715", this is a reference to a dark horse comic about a pirate named Raphal Adolini, who went missing along with his crew whilst traveling along the Bermuda Triangle.
When the Predator is treating his injuries in the bathroom of the apartment, Alex Trebek, the host of Jeopardy! (1984), can be heard giving the final jeopardy "answer": "Berengaria, who never set foot in England, was its queen for eight years after marrying this king on Cyprus?" The "question", in case you're interested, is, "Who is Richard I?"
When Gary Busey's character jumps out to attack the Predator, he shouts, "Guess who's back!" This is a nod to Arnold Schwarzenegger's line in The Terminator (1984), "I'll be back." Schwarzenegger starred in the first Predator movie, and was supposed to return as Busey's character, but turned it down due to a dislike of the script and new director.
In the backstory behind why Dutch, the main protagonist of the first film did not return for the sequel. Keyes had learned of Dutch's encounter with the Predator and he tracked Dutch down to a hospital which Dutch was being treated for an illness from radiation sickness, thought to be a result of exposure of the Predator's Self-Destruct Device. After hearing Dutch's account of events, Keyes and the OWLF team were sent to the jungle to investigate and studied the site where the Predator detonated it's Self-Destruction Device and discover evidence of a spaceship launch in the jungle and that the deceased Predator's ship had automatically returned to the Predator homeworld and Dutch later escaped from hospital and vanished and Keyes personally believed he was still alive.
When The Predator stalks Harrigan at the graveyard. The Predator encounters a boy with a toy machine gun, but does not kill him, when The Predator learns that the toy machine gun is fake and lets the boy live. The Predator is known to kill those who are armed with weapons. If the boy was armed with a real machine gun - The Predator would have killed him.
At one point, while tailing Harrington and King Willy, the Predator is shown perched on a grotesque. The grotesque is a duplicate of the stainless steel eagles that adorn the Chrysler Building in New York.
Several years after the film's release, Gary Busey's son Jake starred as Ace Levy in Starship Troopers (1997), the film which was based on the book by Robert Heinlein is about space marines battling deadly bug like alien creatures. A critic described the film as "Aliens of the 90s". In the final confrontation between Harrigan and the Predator, Harrigan discovers a skull of a Xenomorph in the Predator spacecraft. The crossover film AVP: Alien vs. Predator (2004) was released in 2004.
The trivia items below may give away important plot points.
Bill Paxton is the first actor to be attacked by a T-800 Terminator (in The Terminator (1984)), an Alien (in Aliens (1986)) and a Predator (in this movie). Lance Henriksen is the second, being assaulted by a T-800 in 'The Terminator', the Alien Queen in 'Aliens', and by a Predator in AVP: Alien vs. Predator (2004). Contrary to popular belief, not all of their characters are killed by these creatures: Paxton's character is only violently pushed away by the T-800 and abducted by the Aliens; Henriksen's character is severely wounded by the Alien Queen and shot by the T-800, but neither is confirmed dead.
The writing on the antique flintlock pistol, which one of the Predators gives Harrigan in the end, says "Raphael Adolini 1715". A later Dark Horse comic tells the story of this character, making him a pirate who disappeared along with his crew in the Bermuda Triangle in 1718. This was also the subject of a potential sequel script written in the mid-90s.
During the finale when the elder Predator hands Danny Glover the gun dating from 1715, writers Jim Thomas and John Thomas had conceived an idea for a possible Predator movie which would have taken place in a time where there were no modern weapons available to combat them, much like the finale of the original Predator (1987).
The following scenes were deleted from the final cut of the film: A subplot involving Maria Conchita Alonso's character pregnancy. The chase sequence where Danny Glover tracks the Predator all the way to the slaughterhouse district was extensively longer. Gore and mutilations in all the murders the Predator had done including Bill Paxton's in the tunnel.
For the sequence where King Willy meets his demise at the hands of the predator in the alley, wind and water fans were used to simulate the predator walking on water before it is finally seen during one quick shot as its image is reflected on the water.
With the Alien and Predator franchises crossing over in AVP: Alien vs. Predator (2004), it could be legitimately argued that Bill Paxton's character in this film is an in-joke reference ancestor of his character in Aliens (1986), set many decades later within the same combined story universe. Both characters share a fast tongue and a tendency for bragging.