While Rome took time to build, Francis Ford Coppola’s Roman-themed epic “Megalopolis” tends to crumble within its 138-minute duration.

Despite having grand aspirations, striking visuals, and a talented cast, this sci-fi film (★½ out of four; rated R; hitting theaters Friday) ultimately falls short, becoming a confusing barrage of mixed themes and ideas from a seasoned director. Coppola’s legacy is already cemented with classics like “Apocalypse Now” and “The Godfather” series; however, his track record is marred by some major flops (“Jack” and “Twixt,” for example), and this chaotic venture undeniably fits that category.

The narrative takes place in what is dubbed “New Rome,” a city akin to New York but embellished with a more extravagant aesthetic. (Familiar landmarks like the Statue of Liberty and Times Square receive slight modifications, and Madison Square Garden essentially transforms into a gigantic indoor arena.) The protagonist, Cesar Catilina (played by Adam Driver), is a forward-thinking architect at the Design Authority, gifted with the ability to stop time. He aims to revitalize New Rome using a magical substance known as Megalon.

However, Cesar has made numerous adversaries, including the city’s corrupt conservative mayor, Franklyn Cicero (Giancarlo Esposito). Cicero labels Cesar a “reckless dreamer” who is determined to keep New Rome’s status quo intact. His anger intensifies when his more progressive daughter, Julia (Nathalie Emmanuel), begins working for Cesar and becomes romantically involved with him.

The film has heavy Shakespearean influences, not just reflecting a “Romeo and Juliet”-like subplot, but also borrowing a substantial part from “Macbeth” in one of Cesar’s speeches aimed at rallying the citizens for his grand vision. Coppola’s inspirations are overt – including “Metropolis” and elements of ancient history – and the character names seem pulled from a quirky mix of “Harry Potter” and “The Hunger Games.” The character Wow Platinum, played by Aubrey Plaza, sounds like she could have taught a class on entertainment journalism at Hogwarts.

Supporting characters appear to amplify the oddity of “Megalopolis.” Jon Voight plays Hamilton Crassus III, a wealthy influencer and Cesar’s uncle, while his envious cousin Clodio Pulcher (Shia LaBeouf) harbors his own political ambitions. There’s also Grace VanderWaal, known for her ukulele talent from “America’s Got Talent,” playing a pop star Vesta Sweetwater, who resembles New Rome’s own version of Taylor Swift. Additional characters include Dustin Hoffman as Cicero’s assistant Nush Berman and Laurence Fishburne portraying both Cesar’s driver Fundi Romaine and serving as the film’s narrator guiding the audience through the sluggish plot.

Esposito, while playing the antagonist, provides a much-needed anchor as the film spirals into its madness. Plaza’s performance is flamboyantly entertaining. “Megalopolis” seems to cry out to be a campy B-movie, yet it struggles to embrace its silliness as it veers too far into seriousness. While it certainly attempts bold artistic choices, like utilizing triptychs for storytelling and featuring large statues wandering the streets, the incoherence of the narrative renders these efforts fruitless.

Coppola has labored over this project for over four decades, resulting in something that may only resonate with his most devoted fans and completists.