The trick with keeping a shotgun attached around the arm that Marcus shows Kyle Reese, is used by the older Kyle Reese played by Michael Biehn at the beginning of the original The Terminator (1984), after he saws off the butt to shorten the shotgun he stole from the police squad car.
Director McG asked the cast and crew to read the novel "The Road" by Cormac McCarthy and "Do Androids Dream of Electric Sheep?" by Philip K. Dick - the basis for Blade Runner (1982) - because he wanted them to absorb the bleakness of the world in the novels.
Director McG actually went to visit James Cameron who was working in New Zealand on Avatar (2009) to gain insights and respecting the mythology set in the first two films. It was then that Cameron recommended his art director Martin Laing to work as a production designer and Sam Worthington to play Marcus.
During filming in the summer of 2008, Christian Bale yelled and used profanity at cinematographer Shane Hurlbut, who was adjusting the light in the background while Bale was doing an intense scene and got distracted by the cinematographer. Bale's tirade was then leaked on the Internet. After it was leaked, Bale publicly apologized for his remarks and insisted that he and Hurlbut are on good terms.
Was intended to be the first of a new Terminator "Future War Trilogy", all done by McG, but the films poor performance and reception led to McG being fired and replaced before the next two films ever came to fruition. Instead, a new trilogy is planned to begin with Terminator Genisys (2015).
Earlier drafts of the script before rewrites focused a lot more on just Marcus Wright and Kyle Reese, with John Connor making an appearance in the last few scenes. Christian Bale was first offered the role of Marcus but took more interest in the character of John Connor so rewrites took place to give him more of a substantial role throughout the film.
Just before Connor sets down his helicopter to infiltrate the research facility, the target camera of an incoming rocket indicates the facilities location to be N36° 17'39'' E117° 15'25''. According to these coordinates the facility is located in China, approximately 350km south of Bejing. (See also Goofs)
The third Terminator film to have the line, "Come with me if you want to live." In The Terminator (1984), Kyle Reese says it to Sarah Connor at the Tech-Noir club. In Terminator 2: Judgment Day (1991), the Terminator says it to Sarah Connor when they first meet at the mental institution. In 'Salvation' Kyle Reese says it to Marcus Wright when they first meet. In Terminator 3: Rise of the Machines (2003), a paraphrased version of this line ("Do you wanna live? Come on!") is spoken by John Connor to Kate Brewster when he and the T-850 rescue her in the graveyard. "Come with me if you want to live" is also spoken by Cameron in the pilot episode of Terminator: The Sarah Connor Chronicles (2008), when rescuing the teenage John Connor from the 'Cromartie' T-888.
Christian Bale later stated that before the film, he expressed the same concerns to McG that the Terminator fan-base was expressing about him taking over the franchise. Bale told him that "Nothing in your (McG) filmography suggests that you have what it takes to do this movie properly." McG ultimately convinced Bale to give him a chance so he could "evolve" as a director, but as of 2014 admits that the film "didn't work", insinuating that it was ultimately McG who blew it, and stating that he would never work with McG ever again, though he wishes him well.
In early 2008, Paul Haggis was brought on to polish the script. After he was done, three weeks before filming, Shawn Ryan was asked to rewrite the script, and he took "a pretty big whack" at it. However, he later had to return to television, and the filmmakers "subsequently brought in one or two other writers to continue the work," most likely Anthony E. Zuiker and Jonathan Nolan. So extensive were the rewrites that Alan Dean Foster decided to rewrite the entire novelization after submitting it to his publisher, because the compiled shooting script was very different from the one he was given beforehand.
The river bank used for the napalm strike during Marcus' escape was part of a one-mile man-made river because environmental officials present during the production will not allow them to use the existing river.
Assuming there is small margin of error between the "correct" and "alternate" time lines of the previous films, this installment takes place about 11 and a half years (2018) before the events leading up to the first (2029).
The first recording that John Connor listens to of his mother is an edited version of the recording that she makes at the end of the first Terminator. Moments before the picture that he has and eventually gives to Kyle Reese is taken.
In the opening scene, Marcus is executed by lethal injection using a very accurate prop based on the execution machine developed by engineer Fred A. Leuchter Jr.. As of the release date, this system is only used by four states, mostly due to problems adapting the drug delivery rate for different individuals.
At one point, the film carried the subtitle "The Future Begins." Coincidentally, the film Star Trek (2009) (which opened weeks before Terminator Salvation (2009)) used the same saying as a tagline. Actor Anton Yelchin appears in both films.
This is the first film in which John Connor and his father Kyle Reese have appeared together (if one disregards the Special Edition of Terminator 2: Judgment Day (1991), where Kyle Reese makes an appearance in a dream sequence that was deleted from the Theatrical Version).
The song that plays when Marcus Wright starts the truck in LA is 'Rooster' by Alice in Chains. The song was written by guitarist Jerry Cantrell about his father's experiences in Vietnam (Rooster was Jerry Cantrell, Sr.'s nickname), and the opening line, "Ain't found a way to kill me yet" parallels the movie from John Connor's perspective, with the machines as yet unsuccessful in their numerous attempts to kill him.
The silver-looking machine where the nuclear fuel cells are stored at the Skynet factory is actually a piece of equipment from a semiconductor manufacturing plant, an SVG 90-S coater/developer for silicon wafers.
John Connor and Marcus both use a Sony UX which is the small hand-held PDA device they receive information through and use as an interface to some of the systems, this is a micro PC with a 4.5in screen and weighing just over 1lb.
The film's look is based on Technicolor's OZ (Olson-Zacharias) process, which adds three times more silver to the negative film stock, making it milkier without affecting the grain structure. Although the process was tested in pre-production, it wasn't actually used. Instead, its look was mimicked in the digital intermediate process.
Each Terminator film has been produced under a different company. The Terminator (1984) was produced by Hemdale and went through Orion, Terminator 2: Judgment Day (1991) went through Carolco and Tri-Star (which was owned by Columbia), Terminator 3: Rise of the Machines (2003) was produced by C-2 Pictures and distributed through both Warner Bros. (Domestic release) and Columbia Pictures (international release), and Terminator Salvation (2009) was produced by The Halcyon Company and distributed through both Warner Bros. (Domestic release) and Columbia Pictures (international release).
In the intro, the camera focuses on each letter of the film's title before the words "Terminator" and "Salvation" intersect with each other before being placed in their appropriate places, is similar to the intro from The Terminator (1984).
This was originally intended to be the second half of the two Terminator movies developed back to back by Mario Kassar and Andrew G. Vajna. It was originally titled Project Angel (seen in some computer screens in Skynet during sync sequence with Marcus) and was to be written by David C. Wilson for release in 2003 with the events to start immediately after the first-half, which was Rise of The Machines. However, actor commitments including Arnold Schwarzenegger's office term as Governor of California prompted the script to be rewritten, including moving the time line by credited writers, John Brancato and Michael Ferris, to be supervised and directed by Jonathan Mostow. The project was delayed because in 2006, Kassar and Vajna decided to end their partnership and the movie rights was sold to Derek Anderson and Victor Kubicek.
The shotgun Kyle initially has and is taken away from him by Marcus is a Mossberg 500 typically used for door breaching. Standoff muzzle devices set breaching shotguns apart from the rest and the giveaway feature.
Self-aware robotic killing machines are not too far from reality. The United Nations called for a ban on killer robots, for the fear that several countries are developing them and could threaten the human race. Even Stephen Hawking felt the development of full artificial intelligence could one day spell the end of the human race.
A T-600 is more powerful than quick; it can't observe, evaluate and react all at once. It does have one vulnerable spot, an exposed space at the base of its neck. If attacked there, it loses motor control.
The Terminator that looks like Arnold Schwarzenegger is in no hurry to kill John. John uses a 25mm grenade launcher on it, but it would only stun it or slow it down, not destroy it, and it would still gain on its prey. John always assumed he'd be killed by an Arnie Terminator.
A Terminator's sensors can magnify and analyze substances, like C4, but if it encountered some without a detonator, it would consider it harmless. If a Terminator analyses something new, it adds the data to its individual database.
During filming of a scene. Christian Bale lost it, when the director of photography walked onto the scene and accidentally interrupted the scene and Bale ranted and swore his mouth off and used 39 F-words.
When Marcus is taken prisoner by the resistance, he's held in an abandoned missile silo, the interior is very high up. The resistance brig was used usually for sleeping off too much booze, soldiers who fight amongst themselves or to settle gambling debts from adjoining cells.
In the novelization, Marcus thinks about using the pages of Beyond Good and Evil as toilet paper; Sylvester Stallone wanted to use the swear box sheets as toilet paper in Demolition Man (1993), and both Stallone and Terminator Arnold Schwarzenegger were action movie rivals.
Marcus was suspicious of trust and kindness. He could also swim fast, even underwater. Marcus had been very good at climbing trees as a child. He liked knives because they were always there for him, ready and willing to do what he wanted, which was often. Watching Blair Williams climb down from the tower reminded Marcus of women climbing to escape police custody.
The Harvester that attacked the mini-mart had assorted sensors, both the normal and infrared visual spectrums and ultraviolet. It also has great range to fire at something with more than one weapon. Harvesters place prisoners into Transporters; valuable specimens like Marcus are placed in the forward section. Harvesters have CPU's too. Most people taken prisoner by the machines resigned themselves to death and the ones that didn't were taken away by the Terminators never to be seen again. Some followed their examples only to end the anticipation. The people in the camps wondered if it was a quick death because the machines were efficient, and not prone to sadism, except when extracting information. But they didn't resort to torture because it's deemed an inefficient allocation of resources rather than immoral. Some prisoners were known to go mad loudly or quietly, but the machines didn't care either way as long as they complied. T-600s tattoo prisoners with barcodes on their hands. Reese wondered if they were different for adults and children and did they have an expiration date or were altered in some way. The machines illuminate prisoners like an examination.
The bikes that chase after Reese, Marcus and Star are called Moto-Terminators; they go much faster than a Harvester, their responses are faster than any human driver and Motos also have a very tough outer shell. Moto-Terminators can travel up to 200mph; they home in on sounds associated with human presence. Music means nothing to a Moto because it carried no digital instructions but it could lead them to a human and it was much faster than a human. But although it had a tough exterior, it's innards were much more vulnerable to reprogramming. Motos are not designed to be ridden but can be with difficulty if they're reprogrammed. Motos can do wheelies no human ever could. Motos are mindless and will even go off a bridge to follow their programming.
In the scene when Reese and Star go off the bridge, it's a surprise when the Harvester appears to pluck them out the air; the novelization just tells us. The missiles are A-10 Warthogs, piloted by resistance members Williams and Mihradi (who is uncredited in the film).
Skynet's machines were immune to rain, but they preferred not to operate during heavy downpours; it complicated the electronic perception of their surroundings and could even interfere with their bipedal mobility.
Marcus, Reese and Star are all traveling to San Francisco. Some of Skynet Central made use of the ruins of greater San Francisco; there are self-aware, automated bulldozers that remake the city in their own image and according to Skynet's plan; Marcus wryly thought it might be a distant relative, and would the buildings become self-aware too. The machines were rebuilding San Francisco as an industrial fortress for Skynet, but they had blown up the Golden Gate Bridge. Because it was gone, there were no humans, and Skynet won't waste resources to patrol it. Skynet has placed movement sensitive gun turrets at the end of the bridge that wait before opening fire. John Connor still felt San Francisco had beauty, just not as much of it.
The people at the gas station had stored away packaged and canned food, vacuum-sealed loaves of bread, cans of beer, soda, water and fresh vegetables; the advantages of living outside a major city away from Skynet's control. It was more food than Reese had seen in his life; Reese hadn't tasted ice cream in years. Apples are rare in the future; the resistance tried to keep the base supplied with food, clothing and medical supplies, but fresh fruit was a luxury. There were still orchards but half wild and overgrown that still provided fruit in season carefully picked by civilians.
The cable that snags the T-600 is unbreakable. Terminators will shoot off their own limbs (like the T-600 does) if need be to allow them to complete their mission; even being trapped will not interfere with their directive to terminate someone.
The machine John Connor and the tech team examine is a Hydrobot, which is designed to operate in the water; if it can't carry out its program, it thrashes about like in the film. All Terminators are programmed to recognize John Connor, another reason it was struggling to get free. Although Hydrorobots were eyeless, they had a host of other sensors and razor metal jaws to clamp down and chew through an enemy, even choppers. Because they're only 4ft in length, they attack in numbers to bring down an enemy, and they're tough shell repels most bullets. Hydrobots are useless on land, so the best they could do is fling themselves out the water at someone.
The resistance broadcasted with hidden towers scattered across the continent; they sent out encrypted signals that decrypted at the very end of the transmission. If they were traced by the machines they were rigged to self-destruct through an encryption timer. To prevent tracing, communications would not be completed until the very last moment. The resistance engineering staff assembled their own broadcast unit.
The resistance were losing more every month. But as the voice of the resistance, John Connor would rally them, whatever the end result may be, even though the words never came easily to him. People across the Western United States, parts of Northern Mexico and Utah tuned into Connor's broadcasts as a highly anticipated ritual. Kate Brewster's support helped Connor whenever he was stuck for words during the broadcasts. They were checked so they couldn't be traced. Connor wondered if Reese listened to his broadcasts. John knew the resistance would persevere until all of Skynet's forces were destroyed.
Although the machines believed themselves superior to humans, they had learned not to underestimate them; they maintained a constant vigil for any escape attempts, and the mere presence of a T-600 would deter any; they're programmed to respond to any deviation to the norm, like an empty lift shaft.
Terminators are designed for pursuit, and will scan and follow their prey to the ends of the Earth because they believe termination to be a foregone conclusion. A Terminator will resume its mission if interrupted, as if nothing had happened. If a Terminator is damaged, the machines will send help if they think it's necessary, and destroy a fellow Terminator if it's malfunction is impeding they're mission.
If John Connor were killed, the machines would scan his DNA too. A Terminator's directive to kill John overrode everything else. It would return to its ancillary programming once he was dead and then back to primary.
In the novelization, unrelenting combat had aged some of the troops beyond their years, but still they persisted. Some of the soldiers call John Connor a class-A terrorist, Tunney and David are his backups, and Barbarosa was the team's lead technician. Another resistance member is called Chris. Most of the resistance were good at killing, but only a few were good at the technical stuff. Connor is nearly always solemn, he had learned to stay alive by moving fast, and anyone not made of metal and circuitry was a companion to him, although he did consider Marcus a friend after he saved him from a Terminator. John didn't feel much contentment and neither did anyone else in the resistance. He had seen recordings of old weather broadcasts. John wondered in the book if Skynet naming Marcus Wright meant it had developed a macabre sense of humor. John played back several of Sarah Connor's tapes, memorizing them so from her advice he could learn how to fight back against the machines. He considered them a part of him, just as she was, but he missed her for her confidence and assurance that one day humanity would win and Skynet would be defeated, even when things seemed hopeless. John felt Marcus should be destroyed even if he had saved Williams. John acted less indomitable with Kate Brewster. John lapsed more and more into depression as the war raged on; sometimes Kate could bring him out of it, sometimes not, but he could shake off melancholy and become all business again when the need arose. The war had given John permanent frown lines on his forehead. John never backed away from anything. At the base, John's orders were followed more than anyone else's. John was used to not being listened to; he could never understand why. John only understood the rules on the outside because he made them. John's hands were scarred. Not much could unsettle John in the future but the people herded to their deaths did. John had learned that the best way to beat the machines was to turn their efficiency against them. John considered the possibility the machines may go crazy and start shooting at one another.
In the book, Skynet environments have typically red lighting. Skynet facilities, once up and running, could carry out their programmed functions while the rest of the machines fought humanity and built new facilities, but they couldn't independently track intruders. Skynet will exhaust and starve its prisoners with an inhuman regard for them. Skynet's way of communication is all in code and schematics, cold and disciplined, and the resistance had learned to interpret it.
None of the films after Terminator 2: Judgment Day (1991) are popular. After James Cameron left the series, the copyright passed through several hands, adding to the series drop in quality. These films just vary what Cameron did without the same strength or imagination. Terminator Salvation (2009) was expected to reboot the series, but it was a box-office disappointment so it was a further six years before the next film in the series, Terminator Genisys (2015).
Some of the Terminators that capture people are called Transporters; Transporters are only semi-sentient so are not that bright. The brain of a Transporter is called a neural nexus. Hacking into a Transporter is easier than a Moto Terminator because a Moto has freedom of action and can make decisions but a Transporter can do neither, only what it's told.
Like 9, the main protagonist of 9 (2009) another post apocalyptic film that took place in a post apocalyptic world which robots have taken over the world, which was released the same year. Marcus Wright wakes up in the post apocalyptic world of 2018, with no knowledge of Skynet's nuclear attack upon the world and the Terminator androids.
The more mundane manufacturing activities of Skynet were below ground where the Terminators were assembled by automatons designed to build, not to hunt. They were powerful and single-minded but weren't programmed to deal with intruders. John Connor, Reese and Star considered it a fascinating but horrifying place.
The sailors on the sub (Los Angeles class) treated John Connor with a mix of wariness and admiration. Many of the generals and admirals on the sub made up the world's surviving armed forces. In the novelization, General Ashdown draws a gun on Connor for infiltrating the sub without permission, but not in the film; he's less serious in the book than in the film.
Kate Brewster had gotten used to the sight of bloodstains and never tried to keep her scrubs clean, but although her composure was usually rock-solid, she didn't think she was as strong as John Connor, who even in the darkest moments, managed to bounce back, which is why it was important that she stay alive. Kate knew that things often got worse before they got better. Kate is one of the few genuine doctors the Resistance have.
According to the novelization, Marcus liked the rain because it reminded him of the past he came from. He doesn't feel the cold and is very strong. He can see well in the pouring rain and has extraordinary reflexes. It takes four people to lift Marcus. He is capable of emotion like fear, frustration and impatience, and he doesn't feel pain, but he does feel empathy for Reese and Star, and he can look hungry. He is made of titanium but has veins and arteries. Marcus had a brother. Even Marcus' human eyes are electronically enhanced. Marcus didn't like to deny reality, as he thought Williams did. Marcus thought the idea of a racetrack was wasteful and obscene, even before the war. Marcus felt very alone in the future. Much of his life in the future was, in his words, running, fighting, drinking, drugging and whoring. Marcus couldn't stand the sight of his own machinery because he didn't understand it, but he would have liked the time to examine himself. Marcus can go without blinking. Marcus can survive a fatal fall, precisely gauge temperature and can instantly heal injury. Marcus doesn't feel cramp, his limbs can't be dislocated, he doesn't bleed much, his muscles don't ache, there is no tightness in his arms, he can move faster than a human, and he has a tough exterior against weapons fire. Marcus's night vision was preternaturally sharp. Marcus can steady a motorcycle with one hand; he thinks motorbikes are one machine in the future that's not the enemy, and he can survive a bike crash, being neither human nor mere machine. He can also survive a napalm explosion, but his flesh can be torn away by it. He doesn't tire easily, and his artificial heart beats like a human one; power surges could make his heart skip a beat before circulation was restored. He can walk across the bottom of a river without needing to breathe, but he may be too heavy to swim (like Data in TNG). A part of Marcus wanted to die after discovering the truth about himself. His ignorance made him feel better because it meant his brain was not all machine then. Marcus can absorb knowledge through touching a computer (like the T-1000) at a speed that would overwhelm or kill a human. He could discard new information just as easily. He could scan Skynet Central's database on all the prisoners, and use communications to send a signal that could be picked up by man or machine, including John Connor. Marcus was capable of being infuriated at Serena, because she was intended to be soothing. Marcus feels an internal alarm when injuring himself. Marcus can sound mechanical instead of human.
Blair Williams would be ashamed of herself if she showed pain; her gun is a Desert Eagle. She thought John Connor's calm under fire was both reassuring and unnerving. She knew when to leave John alone, which was how he felt, most of the time.
HK's pick up movement and pursue it without needing daylight because they have infrared to close in on heat signatures. They have main batteries and are programmed to exterminate as well as get reports and scan histories on their targets. The shells of an assault rifle wouldn't damage an HK, it's too heavily armored but it would get its attention and try to find a clear line of fire. HK's have attitude and altitude control. Their Gatling guns could reduce a man to hamburger in less than a minute. The resistance always blow up an HK after deactivating it. HK's shoot guided missiles, even underwater and they have sonar.
The base armory includes pistols, a 25mm semi-automatic grenade launcher with a box of thermobaric shells, a shotgun with sabot shells, grenades, plastic explosives, handguns, a Heckler & Koch MP5 sub machine gun, a 9mm Steyr, a Galil assault rifle that Barnes used and tanks (which the machines use too). Resistance helicopters are equipped with heavy-caliber machine guns, and can use trackers to home in on members with a rescue party.
According to the novelization, the machines protecting Skynet Central are programmed to obliterate anything carbon-based that enters the zone; it was also protected by an enormous wall, integrated gun emplacements and sensors. Skynet didn't need sentries, ambulatory patrols or razor wire; the high-powered instant reactive automated cannons mounted in gimbal turrets detect and annihilate anything organic on the perimeter; machines could pass that by continuously broadcasting their assigned ID to recognized Skynet protocols. Marcus was chagrined that was how he got by. Skynet Central had self-aware loaders, welders, trucks, tiny scavenging devices, multi-wheeled clean-up containers, etc. They all shared the same narrow purpose but Marcus refused to do the same, which made him feel like a man again. T-600s patrol the exterior; Marcus wasn't sure if they would attack him, or would they follow protocol. Skynet Central has a jungle of antennae on the roof, more than Marcus had seen in one place. The ventilation shafts generate so much heat, even the machines need fresh air. The top floor is the command centre, that has more processing power than the planet ever had. Skynet Central uses a series of lights to show if everything is working right; green or white meant yes, red and yellow meant no, but that was rare. Skynet Central didn't have much in the way of sentries on patrol because the machines thought no-one could get past the outer fortifications so wouldn't waste resources. There are inactive machines at Skynet Central like excavators or delivery trucks, mindless servants that lacked sentience and couldn't make decisions on their own without what Skynet programmed into them. Skynet Central was designed to provide easy access from T-1's to larger wheeled machinery. It was their own constructed world, doorless, clean, polished, functional and nothing human. Controls at Skynet Central were straightforward and familiar, a standard Skynet design. John Connor uses a disruptor to short out the door lock at Skynet Central.
The camps where people were brought for extermination were too neat and efficient to be a slaughterhouse but there were bits and pieces of people hung from the ceiling, viscous liquids in tubes, and electrically stimulated arms, legs, organs and torsos, like specimens to be studied. John Connor wanted to help the people being experimented on by putting them out of their misery; some of them are kept in a gelatinous preservative. The machines used disinfectant so the specimens they were studying wouldn't become contaminated. When studying humans, automatic vivisectors are emotionless when dealing with a screaming test subject.
Like 9, the main protagonist of 9 (2009) another post-apocalyptic film that was released the same year as this film. Marcus Wright (A Terminator) wakes up in the post apocalyptic world of 2018 and has no knowledge of the Terminators, SkyNet, John Connor and the war and aids John Connor and the resistance against SkyNet and the machines.
The film's merchandise includes books like The Art of Terminator Salvation, full of color illustrations, storyboards and production art on the movie; Terminator Salvation: The Official Movie Companion, a behind the scenes look at the movie, interviews and commentary from cast and crew and unseen photos; books that continue the story of the war against the machines; Terminator Salvation: The Official Movie Souvenir Magazine, that includes interviews with the cast, behind the scenes with the director and scriptwriters, a look at the new Terminators, photos and concept art; Terminator Salvation: The End Begins, a game where you play as John Connor, leading the Resistance against Skynet, a prequel to the film. Out in May 2009, it was available for Xbox 360, Xbox Live, and PlayStation 3; Terminator Salvation action figures; T-600 and T-700 endoskeletons, 1/6th scale, etc.
Arnold Schwarzenegger said James Cameron "did an extraordinary job creating that character (The Terminator) and whole phenomenon. I never thought we would do a sequel, catchphrases like "I'll be back" or "Hasta la vista, baby" would catch on and be repeated or think that 30yrs later I would be asked to come back to a franchise like this playing The Terminator, unlike Batman or James Bond."
Emilia Clarke became a huge fan of the Terminator franchise after being forced to watch the first two films when she was 7-8yrs old by her 9yr old brother; she later portrayed Sarah Connor in Terminator Genisys (2015).
Arnold Schwarzenegger's favorite moments from the Terminstor franchise are when the Terminator tries to be human because it's something funny and not just action and violence and the most important thing to the Terminator is to blend in, and when he does he fails miserably and that always gets a big laugh from the audience.
The trivia items below may give away important plot points.
Near the end of the movie, there's a confrontation with a newly-minted Terminator with Arnold Schwarzenegger's face. However, Schwarzenegger didn't shoot anything for this movie; the effects team scanned his face from a previous film and applied the result to the stunt double. The result is a character with a much younger face than Arnold possesses today.
A similar desert gas station appears in all four Terminator films. In The Terminator (1984) Sarah stops at one before driving to the Mojave Desert. In Terminator 2: Judgment Day (1991) Sarah, John and the T-800 camp in one for the night after she escapes from the hospital. In Terminator 3: Rise of the Machines (2003) it is where The T-800 stops for supplies and gas. In Terminator Salvation (2009) it is the hideout for the refugees shortly before they are attacked by the Harvester Terminator.
This is the first "Terminator" movie in which a character does not speak the word "Terminated" after killing a Terminator (i.e. "You're terminated!"). However, the word "Terminated" flashes in red on the T-800's internal processor after it thinks it has killed Marcus Wright, a Terminator with a human brain and heart.
All four 'Terminator' films have had their climactic battle scenes take place in industrial settings. The Terminator (1984) saw Kyle and Sarah face a skinless T-800 in an automated factory; Terminator 2: Judgment Day (1991) had the T-800 and the T-1000 face off in a steel mill; Terminator 3: Rise of the Machines (2003) placed John, Kate and the T-850 at Cyber Research Systems, where John and Kate escaped the TX in a particle accelerator; and Terminator Salvation (2009) sees John and Marcus face off with the very first T-800 in a Skynet factory.
In one scene, moto-terminators attack a semi-tow truck driven by Kyle Reese, Marcus Wright and Star as they try to fight the machines off. This is a reference-in-reverse to Terminator 2: Judgment Day (1991), where the T-1000 drives a semi-tower, chasing the young John Connor on a dirt bike. Also, the moment where the moto-terminator jumps off the bridge and lands in front of the tow truck is a reference to the T-800s jump into the canal in T2: the T2 stunt was originally planned to happen the same way but was changed due to safety and budgetary issues.
During the final encounter, the T-800 picks up a concrete block and repeatedly bashes it into Marcus' chest. This is reminiscent of Terminator 2: Judgment Day (1991) where the T-1000 uses a steel girder in a similar manner, crushing the T-800's head and chest area.
John Connor dumps molten steel over a Terminator and then freezes it at the climax. This references Terminator 2: Judgment Day (1991), when the T-1000 was frozen by liquid nitrogen and then thawed out by molten steel at a steel works.
Originally the ending was to have the real John Connor die and someone else, likely Marcus, take up the mantle and assume Connor's identity since very few people actually knew what the real John Connor looked like in 2018. The idea being that anybody could be a hero (in this case, John Connor) and that not only is Judgment Day inevitable, but John Connor and more importantly, the Resistsnce is as well. Sadly, this idea was scrapped when the script was leaked.
John Conner asks Blair Williams "How's that leg ", she says "I'll Live". In Terminator 2: Judgment Day (1991) at the mental hospital, the T-800 shoots the security guard in the leg and says "He'll live".
The "Heart Transplant Ending" used in the final release was an extended reshoot. Originally Marcus just died due to the damage sustained in the fight with the T800. Connor's wounds received in the fight were not fatal either, however this was changed so the transplant could be added in order to give Marcus a more emotional departure.
In the film's original ending, John Connor dies from his injuries and goes robotic. Marcus Wright agrees to have Connor's skin transplanted over his Terminator endoskeleton. But, the John Connor robot is take over by Skynet and wipes out the resistance. The idea of John Connor becoming a Terminator was reused in Terminator Genisys (2015), which an embodiment of Skynet converts Connor into a T-5000.
Marcus Wright was executed and turned into a Terminator in 2003, 1 year before the T101 arrived from 2032 to protect John Connor and Kate Brewster from the TX and to ensure they survive Judgment Day and 15 years before waking up in the post apocalyptic world of 2018 and encountering Kyle Reese and John Connor.