Maybe “Megalopolis” was just an amuse-bouche.

After Francis Ford Coppola’s $120 million movie polarized audiences during the first week of the Cannes Film Festival, the big swings have continued with “The Substance” and “Emilia Pérez,” two much-discussed films that are either stone-cold classics or total fiascos depending on whom you talk to here.

But at a festival where a dozen new movies arrive every day and each title is in danger of being overshadowed, there’s nothing more effective than causing a commotion.

The gory horror-comedy “The Substance” casts Demi Moore as Elizabeth Sparkle, an Oscar-winning actress who, as she ages, can find no better work than hosting an aerobics program. Even that gig is in danger thanks to an unscrupulous network executive (Dennis Quaid) who’s dead set on replacing Sparkle with someone younger and hotter. Backed into a corner, Sparkle decides to inject herself with the Substance, a mysterious fluid that promises a path to rejuvenation.

But this procedure goes several steps beyond Botox and fillers. After taking the Substance, Sparkle’s younger self (Margaret Qualley) emerges painfully from her body and sets about reclaiming the aerobics gig that the network yanked away. The only catch is that Sparkle’s younger and older selves must trade off every week, agreeing to hibernate while the other one goes out on the town. Failure to maintain that balance could have gruesome effects on their bodies, and it isn’t long before this peaceful trade-off becomes an increasingly disfiguring tug of war.

“The Substance,” directed by Coralie Fargeat, offers plenty to talk about, from Moore’s go-for-broke, bare-it-all performance to an outrageous finale that consistently pushes the line on gross-out gore. But the most spirited discussions at Cannes are over whether the movie is trenchant or skin-deep. David Ehrlich of IndieWire praised it as the best of the fest, but several people I’ve spoken to were positively angry about having watched it. Maybe any reaction is the right one when it comes to something so gleefully provocative: In a post online, the writer Iana Murray called the film “shallow” and “painfully unsubtle” but added, “i had a hell of a time though why lie.”

“The Substance” is one of the higher-rated movies on the Screen International critics’ grid, a compilation of reactions that often presages the winner of the Palme d’Or, Cannes’ top prize. But another Palme contender, Jacques Audiard’s audacious “Emilia Pérez,” has prompted nearly as much conversation and debate. A crime drama that’s also a trans empowerment epic that’s also a full-blown movie musical, “Emilia Pérez” is virtually impossible to sum up: Imagine Pedro Almodóvar meets “Sicario” meets Jennifer Lopez’s wacky visual album “This is Me … Now: A Love Story,” and you’re only halfway there.

Part of what makes “Emilia Pérez” so bracing is that you can never predict where the plot will go, so I’m loath to tell you too much. But here are the broad strokes: Zoe Saldaña plays Rita, a disillusioned Mexico City lawyer who’s pressed into the service of Manitas del Monte, a drug lord who wants gender-affirming surgery to live as a woman. The plan is so secretive that it will mean leaving behind wife Jessi (Selena Gomez) and their two children, but there’s much to gain — Rita comes out the other end granted fabulous wealth and the ability to live as she pleases, and Manitas becomes Emilia Pérez (Karla Sofía Gascón), a liberated woman determined to make up for the sins of the past.

Now, while reading that, did you forget this was the synopsis of a musical? “Emilia Pérez” is the sort of movie that’s willing to spike a bloody, climactic shootout with an earnest love song, which is to say, it’s like no other movie at all.

That’s why so many here at Cannes have taken it to their hearts, since Audiard is walking a tonal tightrope that few other filmmakers would dare to tread. Months from now, when some of these wild “Emilia Pérez” scenes are offered up out of context on social media, anyone who hasn’t seen the movie is likely to drop their jaw. But these scenes are plenty jaw-dropping even in context: When Saldaña performs a song-and-dance number about vaginoplasty in a gender-transition clinic, I couldn’t believe what I was watching and I couldn’t wait to talk about it afterward. At Cannes, that’s a big win.