1992 Hugo Winner for Best Dramatic Presentation
This film is a milestone in film making. Not for the plot (it's okay but not brilliant) or the direction (James Cameron does a solid job but it's not nearly as clever as the original Terminator or as well structured as Aliens) or the acting (one word: Schwarzenegger). There's one important reason: the effects.
I was once told that while people were expecting the change from practical effects (models, miniatures, and so on) and CGI to be a gradual adaption process it was actually a cliff. Terminator 2 is that cliff edge. On one side people were getting by with matte paintings and on the other it was nearly all computers and it was Terminator 2 that convinced an industry that computer graphics were the way things had to be done.
In the not to distant future humanity will start a nuclear war despite the valiant attempts by the heroic AI Skynet to stop it. Blaming their attempted savior the remaining bands of humanity gather around John Connor who leads them in a crusade against machines. To stop the neo-Luddites from destroying the last fragments of civilization Skynet sends an agent back in time to convince Connor to go into computer programming. The Luddites don't want to lose their leader so they send a reprogrammed android back in time with two goals: make sure John Connor hates robots and overthrow the governor of California.
Or something like that.
Cameron structured the film almost identically to his original Terminator film, using many of the same lines in different context. The inversion of roles between the sequels was meant that lines like "Ah'll be buhk," (or "I'll be back," in English without the heavy Austrian accent) conveyed something very different. But the structure is the same; two guys from the future trying to change history and chasing each other around. Despite this Cameron manages to give Terminator 2 its own distinct feel.
Part of this is the selection of villain: a liquid robot that shifted forms quickly. It was a familiar concept for science fiction fans but just about unheard of onscreen. It gives the character an extra air of menace as he could change at any moment to become deadlier; it puts the audience on edge as well.
It also made him a showcase for the fledgling computer effects industry and "morphing" entered the common language for the shape shifting effect. The state of the art has come a long way in the nearly twenty years since Terminator 2 was released but it still looks pretty reasonable. It helps that for most of the CGI shots they stuck with relatively simple things and the choice of when to use an effect could serve as an example to other filmmakers.
Naturally as you'd expect from a film where Arnold Schwarzenegger is the headliner the acting is not very strong. The kid playing John Connor doesn't manage to rise about the level of "annoying teenager". Linda Hamilton does the best work in the film reprising her role from the original movie but driven to the edge by the knowledge that the end of the world is coming.
There's one more thing of interest I need to mention in Terminator 2: like Aliens Cameron overshot the film and then pared it back to a tight structure. Much of this footage has been added back in the various "special editions" of the movie but they damage the pacing badly. The best version of the film is the original.
I wouldn't call Terminator 2 one of the greatest movies ever made. On the other hand it is a well made action film that was very influential in film production and that makes it worth checking out. Besides, you can't go wrong with evil future robots hitting each other.