If a product makes money, more of that product will be made. Thrilling films are no different; like horror films, the thriller (or adventure-thriller) is very prone to continuing narratives. This includes everything from spy features to swashbuckling ghost movies, if a movie makes money the studio is going to want to keep the cash cow fat.
However, just because there's more of a good thing doesn't mean the "more" is good. And while that's okay (if an audience grew to love a character, they're naturally going to want more personal time), it still typically means that the sequel doesn't match up to the original.
Pirates Of The Caribbean (2003, 2006, 2007, 2011, 2017)
Even considering how Pirates of the Caribbean: Dead Man's Chest and Pirates of the Caribbean: At World's End are underrated, nothing has ever matched up to The Black Pearl. Disney even tried replicating that success outside the franchise with Jungle Cruise, but it still couldn't come close to the 2003 classic.
While that movie is on track to get sequels, hopefully, they're better than the Pirates low-point, Pirates of the Caribbean: On Stranger Tides. The franchise rebounded by a narrow margin with Pirates of the Caribbean: Dead Men Tell No Tales, but it was still clear the series was dead in the water.
Meet The Parents (2000, 2004, 2010)
Meet the Parents was a big movie in the early aughts. And even after its theatrical run, it became a cable mainstay. So, naturally, it received sequels.
Unfortunately, those sequels were Meet the Fockers and Little Fockers. Meet the Fockers admittedly has a few good quotes and moments but they're typically too crass. All of the sweetness in Parents is removed in favor of foreskin jokes. Then, Little Fockers was a case of putting stars on the screen without a script. Even with repeat viewings, nothing about Little Fockers will be stored in the audiences' memory, which is probably due to the fact that Meet the Parents never needed a sequel in the first place.
The Hangover (2009, 2011, 2013)
The Hangover was anticipated, but few could have seen the R-rated comedy becoming the event that it was. The reason it played well weekend after weekend was the refreshing lack of predictability. It felt like the first comedy in a long time that wouldn't feed the audience clichéd, juvenile jokes.
The mystery was gone in The Hangover II. The breezy energy that permeated Todd Phillips's first film was replaced by a grim tone and perhaps too-high stakes. However, compared to the plotless The Hangover III, the second installment is a suitable follow-up.
Men In Black (1997, 2002, 2012, 2019)
The original Men in Black is one of the ultimate blockbusters. It's breezy, it crosses genres, it has two star-power-fueled performances from Tommy Lee Jones and Will Smith (who have remarkable and unexpected chemistry).
It also has a very poor sequel in Men in Black II. Shockingly enough, that overtly cheeky and kid-oriented (yet overly sexual) debacle came from the same director (as did the solid MiB 3). The most recent installment, Men in Black: International, was an attempted reboot that never got off the ground much less come close to the original.
Iron Man (2008, 2010, 2013)
Iron Man was a juggernaut of the 2008 Summer movie season. It started something with a range that has yet to be repressed (both in scope and box office receipts): The MCU.
Iron Man 2 is seen by many as the Marvel Cinematic Universe's nadir, and while that may be a little strong, the sequel is certainly lacking. Iron Man 3 is a different beast altogether, mostly refraining from employing superhero movie tropes in favor of a half-baked PTSD subplot that unfortunately doesn't reveal much new about Tony Stark. That in and of itself is what puts the first Iron Man on top: it did a great job of establishing Stark (who was not a household name), giving him stakes, and seeing how he reacted to both betrayal and increased power.
The Lion King (1994, 1998, 2004, 2019)
The Lion King II: Simba's Pride is better than most of the Direct-to-DVD sequels Disney cranked out in the wake of successful 1990s theatrical releases. However, even with a returning Matthew Broderick, Nathan Lane, and Ernie Sabella, something is very much missing what was present in The Lion King.
The Lion King 1 1/2 was an interesting take on the franchise, again bringing back much of the original's principal cast for what amounted to a remake (from the perspective of Timon and Pumbaa). However, it still couldn't hold a candle to the original's power, just like Jon Favreau's CGI-filled 2019 remake.
Alien (1979, 1986, 1992, 1997, 2012, 2017)
Ridley Scott's Alien was just about matched by James Cameron's Aliens, but Scott's is seen by many the stronger film. Alien 3 has its merits but is a mess (though the director's cut works). Alien: Resurrection is forgettable at best while the less said about Prometheus or Alien: Covenant the better (both of which had major potential that was squandered in equal measure).
Alien feels ahead of its time even now (which is bolstered by a legitimately notable 4K release for Scott's original). The Nostromo is a detailed, horrifying nightmare in and of itself. Its internal design is as grotesque as anything on the xenomorph, a creature who was never more terrifying than it was here.
Rocky (1976, 1979, 1982, 1985, 1990, 2006, 2015, 2018)
Creed is fantastic, but it's still not Rocky. Stallone's breakthrough is the ultimate feel-good movie. Everything that should be in the narrative is there, and the performances are organic enough so as not to make the saccharine moments overwhelming.
The sequels - mostly Rocky II, Rocky III, and Rocky IV - followed the whole family life-training-fight three-act structure, but to a lesser effect. Rocky V tried something different and became the series' nadir, while the reboot, Rocky Balboa, went the depressing/pedantic angle. And though Creed II has its moments, it's nothing compared to Creed, which is still a sequel that couldn't top Rocky.
Die Hard (1988, 1990, 1995, 2007, 2013)
The Die Hard sequels range wildly in terms of quality. The fourth installment, Live Free or Die Hard is a too-glossy actioner that lacks the Die Hard spirit. A Good Day to Die Hard lacks the spirit even more, with most fans seeing it as holding no redeemable qualities whatsoever.
However, Die Hard 2 and Die Hard: With A Vengeance are solid, rewatchable films. The sequels' standing is a testament to just how impactful the original film is; no matter how excellent the follow-up, there's no besting the audience's introduction to average Joe cop John McClane.
Daniel Craig's 007 Run (2006, 2008, 2012, 2015, 2021)
Casino Royale has just as great a claim to the 007 crown as Goldfinger, so perhaps there was no besting it. However, Craig's run as Bond did get close once. Quantum of Solace is an at-best serviceable film that fell victim to a writers' strike. Skyfall was a significant bounce-back that also set the visual tone for the next two installments.
Skyfall was the pinnacle of Craig's remaining Bond years, but both Spectre and No Time to Die have their merits. The actor's final performance in the role is one of his best, which helps to elevate No Time to Die towards the middle of the Craig pack, but Casino Royale is the apex of his tenure as Bond.