First, a note. Sequels do not typically have a lot of respect. Usually they're seen as cheap exploitation of what worked the first time. Usually they are inferior to the original products. In most cases they don't capture whatever magic made the first one work. Even the list here, reflecting on those typically considered the best sequels, typically don't outshine the originals. In most cases, the sequels are worse, sometimes far worse, than the originals. And that can include being promoted as 'prequels'. Among the worst ever made was Phantom Menace, a movie so bad that it almost tainted the entire franchise. It's also worth noting I'm not considering pre-planned sequels, or manufactured franchises (Lord of the Rings, Harry Potter). Those aren't sequels. You knew they would happen. These are movies that followed ground breaking or outrageously successful movies
that stood on their own, and then forced the movie makers to think 'how can we follow that?' These are the ones they followed in ways worthy of their predecessors.
The Godfather Part II
Not easily. The production was fraught with problems. Neither Brando nor Richard Castelleno would reprise their roles for less than a zillion dollars, so the studios said no, we'll do without. Michael Gazzo stepped in with a character meant to fill Clemenza's shoes, but the storyline still reminds the viewer 'that was supposed to be Pete.' The scene that should have had Brando is also clearly lacking Brando, even if it's minor. The storyline of the post-Godfather plot is essentially the Godfather all over, with the conflicts, the family turmoil, and the obligatory climactic assassination sequence. The development of Michael's relationship and fallout with Fredo is the highpoint.
But it's the 'prequel' version of the story, and De Niro's portrayal of the up and coming Don, that gave it the heft. Roger Ebert once said the sequence in which young Vito stalks Don Fanucci through the streets of a crowded festival is one of the best ever filmed. I'm inclined to agree. Many things went against making this sequel, but through it all, and due to some wonderful filmmaking, especially in the 'prequel' sequences, solidified this film's standing as the best sequel ever made.
Bride of Frankenstein
Like the original, it is based on a stage play of the book, not the book. But it borrows from various elements in the original novel to weave a story that begins to look deeper into the ethical, philosophical and perhaps even theological ramifications of the first. I saw a scientifically funded special on PBS that tried to say, among other things, that Frankenstein was never about scientists going too far. It was, in fact, about silly religious people standing in the way of progress.
I've read the book and watched the movies. It's about what happens when man plays God. And this movie looks to the question with more gusto and yet more subtlety than the first. Karloff is given lines, and he continues to show a monster that deserves at least some sympathy. In fact, Karloff is now not the monster at all. The true monster is Doctor Pretorius. Thesiger brought a new level of evil to this film. In many ways the movie is crueler, meaner in its portrayal of violence and death. In many ways, it's everything the first movie was, but magnified.
In the end, it does what the great sequels do. It manages to link to the original, without merely copying the original and making a formula. It doesn't mimic, and just retell the story. It takes what was there the first time and builds on it, going to new levels and following paths established by the original.
The Empire Strikes Back
Nonetheless, obsession with CGI notwithstanding, most movie critics and many fans over the age of 30 remember this as the best of the crop. Nothing would match the impact of the original. Star Wars was a cultural phenomenon as much as a movie that changed movies forever (for better or worse). Star Wars was to movies what The Beatles were to pop music. When Lucas unleashed his fantasy space movie on an unsuspecting public in 1977, things would never be the same. Star Wars was everywhere. And that phenomenon lasted up until the release of Empire in 1980.
Empire was not as financially successful as Star Wars. And many were put off by the forced sequel ending. Still, when the dust settled, it came to be recognized as the best of the bunch. The final installment, Return of the Jedi, was what it was. A rushed together merging of about three more movies that had to be crammed together due to the actors' increasing reluctance to come back to that galaxy far, far away. And it looks it.
But Empire took Star Wars and went in a new direction. The acting was still what it was. The writing was crisper, and the characters unpacked. If any detractors said anything in 77, it was that the original's story was superficial and the characters underdeveloped. Empire sought to remedy that. Relying heavily on Lawrence Kasden for the screenplay and Irvin Kirshner for directing duties, Lucas stepped back from the trenches and it showed. Better dialogue, a deeper plot, superior writing. The effects still astounded, especially the legendary Walkers segment. But by then, the effects that Star Wars had pioneered were standard issue. And Kirshner knew it. The magic of that summer in 1977 would never be recaptured. But Empire, for at least one movie, tried to say that films about spaceships and galactic empires can be more than matinee fare. They can be quality movies in their own right. Of all the space movies made in the modern era, The Empire Strikes Back comes closest to showing that is true.
A lazy director or producer, when conceiving a sequel, would try again. Suspense. Drama. A similar story. Hapless crew runs into alien part II. But Cameron, who arguably was at the top of his game in the mid-80s, goes a different direction. Realizing what many directors miss, he knew there was no sense trying to scare audiences again, or wow them with fantastical images of derelict spacecraft and strange alien life forms. Instead, he goes a different direction. Action-horror all the way.
Sigourney Weaver, not keen on reprising her break-out role as Ripley, agreed to come back if the screenplay afforded her a chance to be a strong female and also flex her maternal muscles. The movie relies on assumptions of the original movie, and in a way not easily explained, makes knowledge of the original optional. You can actually enjoy it on its own terms. I know this since I actually saw this movie in theaters before I saw the original on VHS, and enjoyed it all the same.
No longer stealth, suspense, a sense of horror. This simply takes the kick-butt monster from the first movie, and multiplies. Then instead of a group of hapless space truckers, you throw in a crack unit of well armed space marines. Chaos ensues. Cameron taps some of his favorite stock actors to fill out a well rounded ensemble cast. From 84's The Terminator come Lance Henriksen, Michael Biehn and Bill Paxton as the scene stealing Hudson ("Game over man, game over!") to help give an extra dimension to what could have been cardboard soldiers backing up Weaver. Aliens does everything right, and in an unusual way, both credits the original upon which it is based, while being a fine stand alone film. Not easy. And seldom accomplished.
And then? Movie magic. Right timing. The Summer of 1975. Beach season. Swim season. Sharks. Need we say more. The mechanical problems helped, and forced Spielberg to rely on Hitchcockian suspense and imagination through most of the movie. It also forced him to come up with a 'shark's POV' approach that only added to swimmers' apprehensions. The acting was superb, with the three principal actors giving wonderful performances, and Shaw's now legendary monologue, which he co-wrote to give Quint a reason for his obsession, still standing as one of the best in movie history. Though it didn't get the Academy Award for Best Picture (losing out to One Flew Over the Cuckoo's Nest), it blew audiences away, caused drops in seaside resort business, and taught Hollywood the power of a seasonally oriented release, soon to be known as the Summer Blockbuster.
So how do you top that? Well, you don't. For obvious reasons, not all of the top three actors can return. In fact, Dreyfus had moved on and only Roy Scheider agreed to reprise his role as Sheriff Brody. Some suspension of belief was needed. After all, given the events of a couple years earlier, why on earth would the town not listen to the man who said 'there's a shark again!' You'd think the entire town would snap into action. In some ways, Jaws II shows what not to do in a sequel.
There are others that are acceptable, and some - such as the Comic Book sequels - sometimes hold their own, even if the movies themselves and their content make a truly captivating film nigh on impossible. I'm thinking Spiderman II, which is a pretty good movie as movies go, much less as comic book movies go. But these are the top five IMHO. And up until recent years in the internet age, there were only one or possibly two that I could see serious students of film disagreeing with.