Robert Patrick undertook a rigorous running regime and practiced breathing only through his nose, in order to appear to be a cyborg that could run at high speeds without showing fatigue. He had trained so hard that he was able to catch up to Edward Furlong on his dirt bike with ease.
Production took sufficiently long that Edward Furlong's growth caused the production team to have to make certain adjustments during the shoot. He is noticeably younger in the desert scene than in other scenes. His voice began to break and had to be pitch adjusted in post-production. He had also grown quite tall over the months that, for one scene shot late in the production schedule, he had to stand in a hole in the ground in order to maintain continuity in height difference with Linda Hamilton.
Linda Hamilton's twin sister, Leslie Hamilton Gearren, was used as a double in scenes involving two "Sarah Connors" (for example, when the T-1000 was imitating her), and in a scene not in the theatrical release (but on the DVD) as a mirror image of Linda.
There was concern as to how realistic CGI would look when it came to the helicopter going under the bridge, so the pilot just did it for real.
Carolco studio executives were nervous and concerned when the original budget of US $75 million ballooned up to US $88 million, with more to come. In order to keep the budget manageable, they proposed to eliminate a few scenes, particularly the opening biker bar scene where The Terminator is introduced. They tried to get Arnold Schwarzenegger to persuade James Cameron to remove that scene, but Schwarzenegger turned them down, saying, "Only a studio guy would cut a scene out like that."
William Wisher: (at around 27 mins) Co-writer Wisher is the photographer during the mall fight when the Terminator is thrown through the galleria window. Wisher also played the police officer who was violently carjacked in Terminator (1984) (hence his look of recognition as he photographs the Terminator).
Van Ling: (at around 21 mins) The DVD Producer and Special Effects Coordinator appears as Dyson's assistant in the lab.
Joel Kramer: (at around 49 mins) Stunt Coordinator appears as the guard in the hospital security room.
James Cameron: [white frame] (at around 48 mins) When Sarah clocks Douglas in the face with the mop handle, a single solid white frame is spliced in at the moment of impact. This trick accurately conveys the flash a person sees when they get hit in the head. It was also used in Abyss (1989) when Cat punches Coffey in the face.
James Cameron: [nice cut] (at around 1 min) During the opening credits, the cut from the playing children to the dark future.