The first thing that most people will notice about Terminator 2: Judgment Day in comparison to The Terminator is its vastly increased budget, the opening battle sequence alone seemingly costing more than the entirety of its predecessor. If The Terminator showcased James Cameron's ability to work within his limits, then Terminator 2: Judgment Day is him showing us what he can do when those limits are significantly higher - it's an ambitious film, and one that almost entirely succeeds at what it is trying to do.
Set roughly a decade after The Terminator, Terminator 2: Judgment Day follows 10 year old John Connor, future leader of the resistance against Skynet, as he attempts to avoid being murdered by an advanced liquid metal terminator known as the T1000. Unlike The Terminator, which has more in common with the slasher flicks that were prevalent in the early 80's, Terminator 2: Judgment Day instead chooses to be an action film first and foremost, handing John a terminator ally in the form of a reprogrammed T800 in order to give him a fighting chance against the bigger threat of the T1000.
It would be hard to argue that this change in focus was a bad decision - Terminator 2: Judgment Day is still seen as one of the greatest action films ever made, and quite rightly so. Think back to the motorbike/truck chase sequence that sees John and the T800 trying to flee from the T1000, or the scene where they try to break Sarah Connor out of the psychiatric hospital in which she is being held, or the SWAT raid on Cyberdyne Systems - these aren't just well-shot action sequences that pushed the boundaries of what could be done at the time, they're also full of these little character beats and instantly iconic moments that force themselves into your brain. Who doesn't remember the way the T800 reloads its shotgun while riding a motorbike, or the bit where the T1000 passes through the barred gate? These moments are, for lack of a better word, incredibly cool, and an important part of why Terminator 2: Judgment Day is both as iconic and it is, and why it doesn't feel as dated as it could.
This focus on action also doubles as a solid reason to bring back Arnold Schwarzenegger as the T800, his popularity as an actor and action hero only increasing since The Terminator thanks to films like Commando, Predator and Total Recall. And he isn't wasted in the role, the film taking the time to humanise the T800 somewhat through its relationship with John. Schwarzenegger was already something of a legend by this point in his career, but I doubt his longevity as an action icon would have been the same without Terminator 2: Judgment Day - this is, after all, the film that created a large number of the lines that people will quote when talking about Schwarzenegger, and it would be fair to say that the T800 is still his most famous role.
The all-important humanisation in Terminator 2: Judgment Day come about because of its relationship with John Connor, who quite clearly sees him as a father figure almost as soon as he realises that the T800 isn't there to kill him. There is a kind of irony here when looked at in broader terms - the thing that is responsible for Kyle Reese's death making amends by taking on responsibility for his son. In a sense, responsibility is a central theme of Terminator 2: Judgment Day - we see it not only in the T800 that has been sent back to protect John, but also in John when he realises that he is in some way responsible for the actions of the T800, in Sarah when she realises she has a responsibility to attempt to stop Judgment Day, and most importantly in Miles Dyson when he accepts responsibility for the future Skynet will create.
His willingness to sacrifice both his work and eventually his life is the ultimate demonstration of this responsibility. This is a character who could so easily have been written as a "bad guy", someone looking to make a quick buck off Skynet and damn the consequences. Instead, we get a fully realised character, a family man who even Sarah Connor can't bring herself to kill for the greater good. His small but meaningful character arc may well be my favourite part of the film, one that concludes with the single best scene in the movie - when Miles Dyson uses his last moments alive to ensure that the SWAT team that just shot him can get clear of the building before he triggers the bomb. It's rare that an action film can create a character as intrinsically good as Miles Dyson and sell them to us, but Terminator 2: Judgment Day does exactly that, and with ease.
As a film fan, it's disappointing that James Cameron has only directed three films in the last 25 years; as an action fan, it's downright frustrating that none of them have came close to being as good as Terminator 2: Judgment Day. It may not be James Cameron's best film - I think we have to admit that The Terminator wins that particular battle - but that does nothing to undermine Terminator 2: Judgment Day's status as an action classic, a status it is still very much worthy of a full quarter of a century after it was first released.