Some moviegoers are already referring to Gladiator II and Wicked as this year’s Barbenheimer — I believe Glicked is the portmanteau of choice. We’ll see if the comparison holds up. Both these lavish spectacles are set to be huge hits, but unlike Barbie and Oppenheimer, they’re essentially known quantities, rooted in stories and characters that the audience knows well.

Wicked was adapted from the long-running Broadway musical, which was itself inspired by Gregory Maguire’s 1995 novel. But you should know, going in, that this two-hour-and-40-minute movie is just Part I, and there will be a year-long intermission before Part II.

The director Jon M. Chu, of In the Heights and Crazy Rich Asians, takes a glossy maximalist approach to this origin story for the Wicked Witch of the West, the villain so memorably played by Margaret Hamilton in the 1939 classic The Wizard of Oz. In this telling, the Witch’s name is Elphaba, and, as played by a quietly commanding Cynthia Erivo, she’s brave, brilliant and grievously misunderstood, mainly on account of her green skin.

Much of the movie takes place at a school of sorcery, basically Hogwarts with Munchkins, where Elphaba impresses the powerful headmistress — an imperious Michelle Yeoh. It’s here that Elphaba becomes rivals with a smug queen bee named Galinda, the future Good Witch of the North. She’s played with delightful comic brio by the pop superstar Ariana Grande. But in time, the two become genuine friends and Galinda decides to give Elphaba a makeover.

Wicked handles the boarding-school comedy with a pleasingly light touch. There’s also a hint of a romantic triangle involving a handsome prince — a very good Jonathan Bailey — who, like a lot of things here, foreshadows future Wizard of Oz developments. In time we get Jeff Goldblum, nicely cast as the Wizard himself, who turns out to be less wonderful than he appears. This sets the stage for Elphaba to harness her full magical strength and become Oz’s Public Enemy No. 1.

Wicked: Part I does build to a doozy of a gravity-defying Emerald City climax, but much of the movie is too lumbering, too obvious, and frankly, too digitally slick to cast a spell. I hate to say this about a movie that teaches us not to judge based on appearances, but I do wish Wicked looked better.

Where Oz has winged monkeys, Ancient Rome has deranged baboons. Early on in Gladiator II, Lucius, a warrior played by Paul Mescal, must prove his mettle by defeating a very scary simian in the Colosseum arena.

Sixteen years have passed since the events of the first Gladiator, and like that movie’s slain hero, Maximus, indelibly played by Russell Crowe, Lucius is a prisoner, scarred by personal tragedy and bent on revenge. His hatred, though, isn’t just aimed at one person; Lucius wants to burn the whole rotten Empire to the ground.

The director Ridley Scott has reunited with some of his key collaborators from that first film, including the actor Connie Nielsen, making a regal return as Lucilla, daughter of Marcus Aurelius. Most of the cast, however, is new: Pedro Pascal plays a formidable general with whom Lucius has a score to settle, while Joseph Quinn and Fred Hechinger romp up a storm as a pair of twin-brother tyrants who are driving Rome to ruin. And Denzel Washington, unsurprisingly, gets the juiciest role as Macrinus, a sly and somewhat inscrutable slaveowner who sends Lucius into the arena.

It’s fun to watch Washington go over-the-top, but his scene stealing is typical of Gladiator II as a whole; it’s a lot of flash, to very little purpose. Mescal, best known for his sensitive, melancholy work in the series Normal People and films like Aftersun, gives an intensely physical performance, but his Lucius never lays claim to your sympathies as commandingly as Maximus did. And when the characters start talking laboriously about the downfall of Rome, and the hope of a glorious rebirth, the movie rapidly loses steam; it’s like watching an extended WWE smackdown suddenly interrupted by a civics lesson.

Still, the smackdown itself is pretty satisfying. In Gladiator II’s wildest action sequence, the Colosseum arena becomes a giant salt-water tank, complete with dueling warships and bloodthirsty sharks. It’s an utterly outlandish spectacle, but Scott, who’s now 86, doesn’t sweat the logistics. The first Gladiator asked, “Are you not entertained?” And in these moments, at least, we are.