Sequels are as sought-after in Hollywood as ever, but what happens when there aren't enough hit movies to go around?

Studios have reached further and further back, making it clear that just about any cult classic or blockbuster is now game for a follow-up. But even then, the well can start looking dry, especially when costly follow-ups like Blade Runner 2049 turn out to be no more popular in 2017 than the original was in 1982 (beloved, but not by a superhero-sized audience). Boundless appetite for movies about Batman and Iron Man doesn't help the majority of studios who do not have the rights to make movies about Batman or Iron Man.

This helps to explain why a movie like Pacific Rim: Uprising exists. If a studio runs out of big hit movies or beloved classics to sequelize, why not turn to movies that may not have been massive hits and have not yet been anointed classics, but were certainly, well, movies that some people saw.

In the past, the counterpoint has been money. The original Pacific Rim did okay back in 2013, but its box office numbers didn't feel like a mandate to spend more money on a follow-up. But sometimes the money doesn't appear until later. One of the most famous cases is the first Austin Powers movie, which did reasonably well in 1997, only to become a home-video hit and have its sequel quadruple its domestic gross in 1999. More recently, the Keanu Reeves action picture John Wick did solid if unspectacular business in 2015. Lionsgate saw enough interest for a sequel, and John Wick Chapter 2 was a bona fide hit.

Pacific Rim feels different from those movies, though, because there isn't anything particularly scrappy or unlikely about an expensive sci-fi action movie where Godzilla-like monsters attack the globe and humans in enormous robotic armor attempt to fight them off. This despite the fact that the first film was directed by Guillermo Del Toro, whose monster mashes usually feel, if nothing else, extracted from both his brain and heart. Pacific Rim is an enjoyable riff on the giant-monster movies that inspired it, but it's an unlikely choice for anyone's favorite Del Toro movie. Technically, it was his biggest-ever hit, but it wasn't exactly a sensation. He hasn't returned to direct the sequel, only produce it, and original studio Warner Bros. happily traded its distribution rights over to Universal.

That leaves Pacific Rim: Uprising feeling like even more of a gamble than the original; it looks just as expensive, rife with impressive monster/robot effects, and digitally rendered destruction, but it answers a lot of questions that few fans were likely asking. In a way, this makes it a perfect companion piece to Pacific Rim. It's utterly inconsequential but committed to fully imagining its inconsequentiality.

The movie picks up a decade after the original, in a world that is still recovering both physically and mentally from the monster attacks. The early section follows Jake (John Boyega), the son of Idris Elba's heroic leader from the first film, bumming around a coastal area ravaged by the initial monster war and now something of a no-man's land, full of beastly skeletons and scavenged robot parts. It's not unlike recent sequels to Independence Day and Transformers in that it's willing to examine what the world looks like after the apocalyptic destruction of a typical blockbuster, but director Steve S. DeKnight is by turns less bombastic and less cornball than his old-guard competition.

Pacific Rim: Uprising also makes some gestures toward increased kid-friendliness — yes, more kid-friendly than the first movie that pit giant monsters against giant robots. Stylistically, the battles are brighter-lit and less moodily evocative than Del Toro's; DeKnight makes them look a bit more like a mega-budget Power Rangers episode, and his handling of suspense and action is similarly weightless. The movie also brings in a younger crew of soldiers who must enter a neural "drift" to pilot the robot-crafts, including scavenging orphan Amara (Cailee Spaeny).

It's neat that the movie presents a kickass girl as one of its heroes, but it feels a bit like a half-measure; in between check-ins with Amara and her vague mentor-mentee relationship with Jake, the movie goes off on missions with Jake and his frenemy Nate (Scott Eastwood, making it more apparent than ever that he's the son of Clint). As before, there's plenty of jargon-y world-building, and though this movie arrives only five years after its predecessor, it often plays like a legacy sequel to a beloved 20-year-old original that must serve both the new characters and the beloved returning faces.

The fact that this strategy is semi-nonsensical — Boyega and Spaeny are more fun than many of the original characters anyway, and to the extent that the "legacy" characters are served, they're often in some manner betrayed — doesn't really hurt Pacific Rim: Uprising. Its inessential, unrequested nature inures it against many of the usual sequel disappointments. If you liked Pacific Rim, you'll probably like Uprising, too. It might even leave a generation of kids wanting more.

But it's a sequel that makes the original seem more sequel-worthy than it probably is.