In an interview, Michael Biehn stated that working on this film was "probably the worst experience of my life".

The actors spent two weeks in an intensive SEAL-style "boot camp." In the end, it was actors versus SEALs in a final "war game" showdown. The SEALs are reported to have graciously said that the actors made a good showing for themselves.

Originally, the men were going to play touch-football. But Bill Paxton felt the scene was too similar to the volleyball scene in "Top Gun (1986)." So he suggested that they play golf instead. Most of the golf sequence was directed by Paxton with a second unit crew.

When discovered by a terrorist who tries to speak to him, Hawkins shoots him without answering, then says, "Boring conversation. Leader, we're gonna have company!" imitating a similar line by Han Solo in Star Wars: Episode IV - A New Hope (1977).

'Chief Dave' one of several real-life SEALs who would later play themselves in the film 'Act of Valor' cites this film as his first introduction to the world of SEALs and inspired him to join them.

Despite those named in the credits, the film went through another draft by Kevin Jarre. In one draft, Hawkins (Charlie Sheen) sacrifices himself to rescue Curran (Michael Biehn), who ends up with the love interest. In another version, Curran is killed off rescuing some kids, and Hawkins and Claire Varrens (Joanne Whalley) are left to mourn his passing. Also in one of those drafts, Curran is an accomplished boxer who squares off in a fight with Hawkins, who's into karate. The golf sequence in the film was a concession when the film's leads objected to a Top Gun (1986)-style scene with knife-throwing contests and bikini bimbos.

Several events in this movie are inspired by Chuck Pfarrer's real SEAL career.

Michael Biehn, Rick Rossovich and Bill Paxton all had roles in "The Terminator" (1984).

In the warehouse scenes with the missiles, the containers have markings that refer to the "Redeye" M41 missile system, a predecessor to the "Stinger" that is referred to in the film.

During the segment at the golf course, Leary (Rick Rossovich) is seen wearing a Martini Ranch t-shirt. Bill Paxton, who plays Dane, was a member of the '80s rock band Martini Ranch.

Chuck Pfarrer, the film's co-screenwriter and a former Navy Seal, plays an uncredited part as an officer on the aircraft carrier who debriefs the Seal team after their first mission, his character being the one getting into a heated discussion with Lt. Curran (Michael Biehn) regarding the Stinger missiles. Many of the missions seen in the film are based on real top secret missions that Pfarrer had himself taken part in.

Denis Haysbert who plays the role of 'Chief' would later go on to play the leader of the Delta Force in the TV series 'The Unit'.

Much of the filming took place in and around Norfolk, Virginia, home to world's largest Naval fleet. The production crew was able to shoot key scenes in such restricted areas as the Norfolk base and its training grounds.

Both Michael Biehn and Bill Paxton appear in this film together, 4 years earlier they also appeared together in Aliens (1986).

To simulate the formidable training that Navy Seals go through, the actors playing the Seals went through a two-week indoctrination course at a special training center in Winchester in northern Virginia. After becoming familiar with the weapons they'd soon employ on film, the actors took part in field maneuvers. Actor Charlie Sheen recalls: "It was very extensive and very physical. The concentration was on urban combat, door-to-door and hand-to-hand. We learned how to handle weapons, how the chain of command worked, and the scope of international terrorism. It helped us understand the SEALs' presence on the world scene, and their unusual sense of duty".

The film was partly shot in Spain. The submarines, warships, helicopters, and planes that are seen in the film mostly belong to the Spanish Navy/Air Force, which gave the production full co-operation. In one scene, set on an aircraft carrier, you can actually see a Spanish flag flying in the background while the Seals are on the ship's elevator being raised from the hanger up to the deck, ready to set off on their final mission.

Describing his time working on this film upon its release in summer 1990, actor Michael Biehn stated: "It was a tough, demanding, exciting film to make. It had to be. Working with the SEALs and portraying them was its own reward - an incredible experience. They're a breed apart. They're unique."

The ancient city of Cartagena, Spain served as a principal location. Much of the Spanish Navy is stationed in its well fortified harbor while the crumbling inner city neighborhoods, with their steep, cobbled streets and blanched Moorish houses were used to recreate the war-torn sections of Beirut, Lebanon. The Cartagenians were good hosts who took things in stride while the film crew dynamited buildings, set vessels ablaze in the harbor, and fired machine gun volleys into the normally still night air.

The Ready Room Bar and Pizza is still open although a fire destroyed many of the memorabilia items signed by the cast.

Actors Michael Biehn, Bill Paxton, and Rick Rossovich also appeared in the films The Terminator (1984) and The Lords of Discipline (1983). Biehn and Paxton had already played comrades in Aliens (1986). In an interview promoting the movie, Michael Biehn stated: "Working with Bill and Rick was especially beneficial for this picture. SEALs are a team, and we've worked together so often that we already know what to expect from each another. Hopefully, it shows up there on the screen." In another, more recent interview, Biehn said that their involvement together was intentional: "I think I called Lewis Teague (director) when we were doing Navy Seals, and said what about Bill Paxton, and y'know, I mean we all liked each other, we were all buddies, young and hungry back then, so yeah, we were pulling for each, definitely".

Both Micheal Biehn and Bill Paxton also starred together in "Tombstone."

Adam Brown, a highly commended member of SEAL Team Six who was tragically killed in action in 2010, was inspired to become a Seal after watching this film, particularly the scene of Hawkins (Charlie Sheen) jumping off a bridge, a stunt which Brown himself recreated in his youth when he jumped out of the back of a moving truck as it sped across a bridge, falling 50 feet until he hit the river below.

Former SEAL Chuck Pfarrer was the film's co-writer and technical advisor. To help ensure the film's accuracy, Pfarrer enlisted eight additional former Navy SEALs to train the actors in their roles and, occasionally, perform specialized stunts. The producer Bernard Williams explains: "A lot more than stunt work was involved, however. Each actor had a SEAL double to whom he could turn for help in handling weapons or perfecting SEAL techniques. They were an on-the-spot source of vital research, to make the movie as much like the real thing as possible".

All the various battle scenes in the film were shot in locations across southern Spain in such ports as Tarifa, Cadiz, Rota, and Cartagena where the old, walled cities and an arid Mediterranean coastline made it very similar to the Middle East. The Spanish military made a major contribution, providing soldiers to play the numerous terrorists for the battle scenes, and loaning machines to the production including M48-A5E Patton tanks and M113 Armored Personnel Carriers, to give a more authentic feel to the film.

The main weapon used by the Seals throughout the film is an MP5-SD3 with a built in suppressor/silencer. It is a German made sub-machine gun that's popular with Special Forces teams due to its suitability to the type of close-quarter battles you see in the film and also its relatively compact size. The handgun of choice with the Seals in the film is the Beretta M9 sidearm.

The character of Dane, callsign "God", played by Bill Paxton, is the Seal Team sniper and uses a Barrett M82A1. It is a recoil-operated, semi-automatic sniper system capable of firing high powered .50 caliber rounds at military equipment and enemy personnel. The weapon in the film is outfitted with a combination Thermal Imaging Sight and Star Light Scope.

Seal Team roles: 1st Lt. James T. Curran, SEAL team leader. Played by Michael Biehn. Lt. J.G. Dale Hawkins, second in command. Played by Charlie Sheen. Sgt. James Leary: Medic. Played by Rick Rossovich. Petty Officer 2nd Class, Floyd 'God' Dane: SEAL Team Sniper. Played by Bill Paxton. Homer Rexer: Explosives Expert. Played by Cyril O'Reilly. Ramos: Radioman & interpreter. Played by Paul Sanchez. Billy Graham: Chief. Played by Dennis Haysbert.

Actress Joanne Whalley researched her role by interviewing journalists who have covered the Middle East, and by reading reams of news copy. Whalley stated that she chose to make the character of Claire Varrens: "an amalgam of reporters I've met and talked with. Every one of them would have tried very hard, like Claire, to get first hand information on the top secret SEALs as well as the terrorist factions of the Middle East".

In the wedding scene in the start of the movie it is "Prince of Denmark's March" which is played. It was also played during the wedding of Lady Diana Spencer and Prince Charles at St Paul's Cathedral in 1981.

Michael Biehn and S. Epatha Merkerson are both featured in "Terminator 2: Special Edition."

In the Ready Room bar scene after the Chief's funeral, the local patron who calls one of the Seals "Squidly" is Titus Welliver who would go on to have his own series on Amazon called Bosch (2014).

The character played by Bill Paxton uses an earlier model of the M107 fielded by US Army in the 2007. In one scene he's shown switching the optic from Night Vision ("Starlight") to Thermal mode, allowing him to see targets hiding behind walls. While image intensifier optics have been in use since the 1960s, at the time this film was made thermal imagers were actively cooled, making them far too large and noisy to mount on even a large rifle. On top of that, even modern thermal imagers can't see through walls, and are even blind to glass. The primary advantage of thermal imagers in combat is that warm human targets stand-out against a cooler background, making it easier to acquire a target.

Dennis Haysbert and Charlie Sheen starred together in Major League (1989) The year before this movie was released.

In the final mission to Beirut, the Seal Team use AK-47 assault rifles despite that being the weapon of their enemy along with using some Arabic head attire (which they hadn't done on previous missions to the Middle East). This is done because at that time Beirut was engulfed in fighting between various rival factions (including Druze, Amal, Hezbollah and the fictional Al Shuhada in the movie), so the SEALs could thus blend in and be taken for any urban guerrillas already there. The AK also has a distinctive sound unlike the usual western machine guns which would also help with them being incognito.

The character Leary, played by Rick Rossovich, fires a FIM-43 Redeye (standing in for the Stinger missile) to destroy the enemy APC that is pursuing them in Beirut, even though some creative license was used as such missiles can't be fired at ground targets.

Other weaponry used by the Seals include: M67 "baseball" hand grenades (used by Hawkins to blow up some gas tanks and a crate of Stingers); Remington 870 sawed-off Shotgun (used by Hawkins to blow open a locked door); FN Minimi aka the M249 SAW (used by Ramos on the third mission); Colt Commando XM177E2 (used by Leary on the third mission); M203 grenade launcher that's under-slung with an M-16/XM177 (used by Rexer on the third mission). Leary also uses a variant of the RPK on the final Beirut mission; and an MP5K is briefly used by several Seals throughout.

The Seals use the Sikorsky SH-3 Sea King, a Naval anti-submarine helicopter, for extraction during the first mission and again for the last mission to Beirut. The Lockheed C-130 Hercules, a transport plane, is used for the HALO parachute jump. Aircraft carriers seen throughout include the USS John F. Kennedy and USS Coral Sea which are shown docked in the Norfolk Naval Station, a Navy base that is home to the US Atlantic Fleet.

The heavy vehicle that chases the Seals through the streets of Beirut is a BTR-152. It's a Soviet armored personnel carrier (APC) from the 1950s, armed with twin-mounted Browning .30 caliber machine guns. It was loaned to the production by Spanish armorers who most likely got it from a western army that had captured it.

They used Marines from the USS John F. Kennedy for scenes that did not make it in the movie. The aircraft carriers that are in the scene of the dock are the Kennedy and the USS Theodore Roosevelt. Those Marines can be seen in a glimpse on the deck of the Kennedy.

Joanne Whalley was married to Val Kilmer at the time of this movie. Val Kilmer appeared in Top Gun.

Screenwriter Angelo Pizzo wrote an early draft of the screenplay.

The three pinball machines featured in the bar scene are Bally's Fireball II (1981), Gottlieb's Devil's Dare (1982), and Premier's Arena (1987)

There are high explosive, armor piercing, incendiary .50 BMG rounds available for use by the military. The scene of the sniper shooting these kind of rounds is entirely possible.

Rick Rossovich starred in Top Gun and Charlie Sheen starred in Hot Shots. A parody of Top Gun

Richard Venture who plays Admiral Colker also played Colonel Meyers along side Clint Eastwood in Heartbreak Ridge

One of numerous films to feature a heavily-wounded Michael Biehn being carried away from danger by comrades. Others include The Terminator, where he is held up by Linda Hamilton, and Aliens, where Sigourney Weaver basically hauls him around like a ragdoll.