A producer from Carolco Pictures called James Cameron and told him they'd bought the rights to The Terminator and wanted a sequel made -and they wanted it ready in just over a year. Cameron hadn't considered a sequel. After all, The Terminator was released in 1984 when sequels were not expected, and he'd killed off almost all the characters. Still, he and co-writer William Wisher came up with a script for Terminator 2 in six and a half weeks. Although the idea of spoilers was not as pervasive in the days before widespread internet use, that script was well-guarded because the element of surprise would be important to the story. Co-producer Stephanie Austin talks about the secrecy.
“We were all onboard because it was unusual,” she said. “And until the trailer came out, nobody really understood how you could make a sequel to The Terminator because of the way the first one ended. So there was a lot of secrecy, a lot of confidentiality, and a real need to keep that under wraps until we could make the big reveal.”
That big reveal didn’t happen in the media either. Austin explains it wasn’t until audiences first got a glimpse at the teaser trailer that the ideas behind the movie were revealed—specifically that Terminators could be mass produced.
And we still didn't know that Arnold Schwarzenegger would be the good guy this time. That surprise only added to the movie's popularity, which is hard to imagine when you watch it today. It was a $100 million-gamble that paid off. Read more about the making of Terminator 2: Judgment Day at io9.