Spoiler warning: this review reveals important ending details from the original 2014 Lego Movie.

The most innovative, daringly different hit projects face two major downsides: the backers are going to want sequels, and the more distinctive a project is, the higher the difficulty level on that sequel. Phil Lord and Chris Miller’s 2014 blockbuster The Lego Movie is an excellent case in point. The entire idea of a Lego-based movie looked like the baldest, most mercenary toy-commercial setup for a film that product placement gurus could possibly imagine. But Lord and Miller turned it into a meditation on creativity and childhood joy, with a side order of side-eye at some big, well-worn fantasy tropes, like the prophesied “chosen one” hero. And they wrapped it all in a stunningly fast-paced joke-delivery system, built around startlingly elaborate animation, and pegged to an inescapably catchy song.

So how to follow up on a film that created a world, then upended it by revealing at the climax that it wasn’t what audiences thought it was? There’s the standard sequel toolkit: “Go bigger, louder, and simpler.” There’s the complete-pivot strategy that the Lego Movie spinoffs The Lego Batman Movie and The Lego Ninjago Movie took, by focusing on different characters in the same setting. And then there’s the Harry Potter / Toy Story playbook, where the creators try to let their franchise grow up a little alongside its audience, using the same characters, but darkening the tone and reaching toward more mature themes. As writers and producers (though Shrek Forever After’s Mike Mitchell has taken over directorial duties), Lord and Miller nudge toward that last option — sort of. With The Lego Movie 2: The Second Part, they let the story grow up. But in the process, they make fun of “growing up” stories, just as they made fun of “chosen one” stories in the first go-round.

The Lego Movie introduces Emmet Brickowski (Chris Pratt), an ordinary little Lego dude who’s totally average, apart from his obscenely chipper demeanor and his inexplicable role as “the Special,” a prophesied savior for his threatened Lego world. When a mysterious force threatens his town of Bricksburg, he saves the day — in the process revealing that his world and its story are a game being played out in the human world by a boy named Finn, who’s being creative with his dad’s extensive Lego sets. As the film ends, Finn is joined by his baby sister Bianca, who wants to play, too. Suddenly, Finn’s Lego world is threatened by Bianca’s toys, a series of crude, baby-voiced creatures made from Lego’s toddlers line, Duplo.

Lego Movie 2 briefly takes up at the exact moment where the first film left off, with the “aliens” from “the planet Duplon” smashing their way through Bricksburg. Then the action leaps five years forward, as grim heroine Wyldstyle, aka Lucy (Elizabeth Banks), explains that since anything remotely shiny or bright attracts the invaders’ attention, Bricksburg has become a dark, gritty post-apocalyptic dystopia as a form of defense. Various figures from the first film, including Unikitty (Alison Brie) and the pirate Metalbeard (Nick Offerman), have taken on grimmer, butcher personas, though spaceship-crazy astronaut Benny (Charlie Day) seems pretty much unchanged. (Will Arnett’s Lego Batman was always apocalypse-ready, though he does have to take a stressed-out moment to explain why Robin and Batgirl from The Lego Batman Movie have vanished, supposedly to please the fans who prefer Batman as a sullen loner.)

Emmet is similarly unchanged, and accepts the apocalypse with his usual upbeat obliviousness. That seriously offends Lucy, who wants him to grow up and go dark with the rest of the world. Then a mysterious invader kidnaps Lucy and the rest of the crew, and Emmet has to seek help from a reckless badass named Rex Dangervest in order to become tough and serious enough to save the day.

The Lego Movie had its notable flaws, particularly the way it introduced Wyldstyle as a world-beating badass, solely so Emmet could casually surpass, rescue, and win her. But Lord and Miller whisked the film so quickly and joyously from Lego world to Lego world, highlighting creativity, color, and good cheer, that it was impossible to fixate on any one plot point or character portrayal for long. The visual and verbal gags came at a staggering if-you-blink-you’ll-miss-something rate, as if trying to keep viewers overwhelmed and hypnotized. The sequel actually slows down the story a bit, with a lower jokes-per-second rate and a little more time for contemplation. But instead of making the new film smaller or duller, it leaves room for a little more sophistication. The sequel’s best gag isn’t a one-liner or a one-off, it’s subtly and fundamentally built into the story.

Where the first film withheld the big meta reveal for the end, Lego Movie 2 foregrounds it, without expressly spelling it out. The entire movie is a push-and-pull between Finn and Bianca, between the imaginations of a surly teenage boy and an energetic young girl. Finn’s tastes push Bricksburg toward its ruined apocalypse state, where the residents brood over the wreckage caused by Bianca’s hyperactivity and excitement. But they also embrace it, with a sullen kind of pride in their own ferocity. Meanwhile, Bianca’s more emotion-driven, chaotic form of play fills the city with exploding hearts and stars that speak with toddler voices. Her contributions to the make-believe world break down order and introduce a random chaotic element.

And Bianca introduces a new character, the perpetually shape-changing Queen Watevra Wa’Nabi, voiced by Tiffany Haddish. The queen’s name, pronounced “Whatever I wanna be,” is an open announcement that Bianca is playing without limits, embracing whatever whim strikes her fancy, and shifting form to fit the moment. That lack of structure comes across as erratic and unpredictable for the characters caught in the story, but for the viewers, it’s a blast.

The most impressive thing about The Lego Movie 2 is that it doesn’t explain any of this outright. The action does periodically pull back to show what’s going on in the real world, to explain why certain things happen in Emmet’s Lego reality. (It’s a bit like the shifts between a child’s playtime and the imaginary world the toys are experiencing in the Toy Story movies, except that all the Toy Story characters are aware of and love their human owner, while most of the Lego characters are unaware of the human forces shaping their lives.) But there’s never any outright narration or exposition to clarify how Finn and Bianca’s sibling rivalry is shaking the Lego world. It’s left for viewers to pick up on their own, as a rolling meta-joke that gives the entire story an added level.

But the gag that the whole story is just a game for a couple of children plays out on a third level as well, and that one has a little poignancy. Again, without expressly spelling out her feelings, Bianca seems to resent that Finn is getting older and fixating on “mature” games — that is, the grim-n-gritty, humorless, dour stories that have been such a source of conflict in comics and films ever since Watchmen and The Dark Knight Returns. And that plays out in their shared pretend narrative, as Emmet tries to “grow up” to please Lucy, and finds some major clichés standing in the way. The film winds up making fun of both the grim-n-gritty movement and the entire idea of maturity, which it presents as a lot less fun than childhood innocence and unselfconscious play.

So much of Lego Movie 2 operates on the same level. Viewers are constantly in on the meta-humor that the characters miss, from the many jokey voice cameos (including Jason Momoa reprising his role as Aquaman) to the conscious calculation of a dance-music song called “Catchy Song,” which incessantly repeats the line “This song’s gonna get stuck inside your head!” When Queen Watevra Wa’Nabi sings a heavily ironic song called “Not Evil,” where she unconvincingly promises she isn’t a villain, the movie reaches a point of tongue-in-cheek where it’s gloriously impossible to tell who’s actually being sincere.

And that level of playfulness ends up making Lego Movie 2 an impressive experience, even when it can’t live up to its predecessor’s surprises and innovations. The new film hits many of the same beats, from Mark Mothersbaugh’s bouncy electro-score to some of the same character gags. (Batman: still extremely into his own hype. Benny: still extremely into spaceships. Lucy: still pretty naggy and insecure about whether other people see her as enough of a badass.) Its constantly changing and rebuilding world is still startling, but apart from the dazzling work on Queen Watevra Wa’Nabi, a lot of the novelty is gone at this point. The closing-credits song featuring Robyn and The Lonely Island is hilarious, but little more than an add-on after the meat of the movie is over. On the surface, Lego Movie 2 is smaller and less ambitious than the series’ kickoff film, and it’s less frantic and funny to boot. It has fewer fantastic worlds, and less to discover in them.

But seen as a narrative that constantly operates on both an adventure level and a meta-level, as a functional thriller and a satire of its own genre, it’s a stunningly smart, wry project. It’s appropriate that a movie about construction toys is so entirely devoted to deconstructing familiar heroes-and-villains stories, and that a movie about kids playing would spend so much time playing with genre. Just like the first Lego Movie, the sequel goofs around with constantly shifting forms, and the themes of creativity and creation. It ends up feeling like more than an obligatory cash-in: it builds a whole new layer on top of the Lego Movie foundations.