When I was sitting in judgment before modern cinematic debacles such as Richard Kelly’s Southland Tales and Darren Aronofsky’s mother!, I didn’t let my mind wander to speculation about what a more experienced, capable director might craft when surfing a similar tsunami of clanging metaphors, ostentatiously self-conscious technique, and go-for-broke acting. For anyone who might by inclined toward such mental exercises, the answer key is at the ready now that Francis Ford Coppola has finally delivered the magnum opus that has preoccupied him for at least a few decades. Megalopolis, which Coppola directed, wrote, co-produced, and self-financed is astounding in every way. It is auteur filmmaking as a runaway train, throwing off ideas like sparks when the wheels rub unevenly against the tracks.

The film takes place in a slippery-satire alternate version of our own reality, where the teetering American empire has conveniently apt representation in a version of New York City that borrowed and maintained most of the trappings of Ancient Rome, just giving them an art deco spruce up somewhere along the line. One of the key figures in the city is Cesar Catalina (Adam Driver), head of the Design Authority, which imperiously demolishes existing infrastructure to make way for his kooky utopian-dreamscape constructions made out a sturdy-yet-pliable cosmic brick of his own invention called Megalon. He’s opposed in his efforts by the city’s floundering mayor, Franklyn Cicero (Giancarlo Esposito), and a shifting array of antagonists who emerge and recede on the basis of creative whim more than narrative logic.

Megalopolis somehow is overstuffed with ideas and yet radically underthought. It seems every loopy notion that popped into Coppola’s head during the protracted development process of the film is given a home within its frames, whether fourth wall breaks, jarringly resplendent imagery, or Driver lifting a Hermann Hesse paperback briefly into frame like a visual footnote. There is a villainously ambitious TV news financial reporter named Platinum Wow (Aubrey Plaza, reveling in the absurdity) and a Swift-tian pop star named Vesta Sweetwater (Grace VanderWaal). The latter’s virginity is celebrated in a municipal fundraising auction that takes place at a lavish, Roman Circus–styled wedding reception staged within Madison Square Garden. It’s that kind of movie.

In part because this type of imaginative largesse is almost entirely extinct in the modern cinematic marketplace, I found Megalopolis to be entertaining. At the same time, Coppola’s fundamental themes and purposes are too confused for the film to be satisfying or even entirely worthy of the simple descriptor “good.” Cesar Catalina is akin to Robert Moses, the New York public land planner made famous by Robert Caro’s massive tome The Power Broker, but the despotic and self-destructive pieces of the character that are bundled with that influence are occasionally shunted aside so he can be a stand-in for misunderstood artistic genius, a longtime Coppola fixation. A spoiled-rotten scion of a wealthy family, played by Shia LaBeouf, engineers a rise on the back of class grievance and welling political violence. The subplot might work better if Coppola had a more cogent take on an enlightened society on the verge of collapse. Then it would snap into place like a Lego brick. Instead, it’s a whole lot of noisy bustle he can cut to every now and again, as if to say, “This is just like current events, right? Right? See their red hats?”

There so much ambition driving Megalopolis that the film becomes about nothing more than its own existence. Whatever Coppola might have initially intended all those years ago, in the here and now it was made not to convey anything much that fact that it was made, that the system couldn’t thwart him forever. Given the filmmaker’s history, that is maybe apt. Now eight-five years old, Coppola is unlikely to direct another feature, making Megalopolis his final signature upon the screen. For better or worse, the film certainly contains his multitudes.