Most organized-crime dramas are structured like chess, two families knocking each other off the board while their pawns try to become kings. Ben Affleck’s Live by Night — which he wrote and directed — is a Prohibition-era gangster picture crossbred with a video game, where Affleck’s quest to control the bootleg rum business up and down the East Coast plays out like Super Mario Bros. Every time he defeats one boss, he levels up to someone harder, from country-boy distributors to the Cubans to the KKK.

Like Mario, Affleck’s Joe Coughlin is a high-energy, coin-loving hustler who’s hard to kill. He’s even got a princess or two, a brassy blonde named Emma (Sienna Miller) and, later, Cuban molasses importer Graciela (Zoe Saldana), who favors scratchy backless dresses. The only difference is that Joe isn’t Italian, which matters when his employer, Maso Pescatore (Remo Girone), is. On the Mafia battlefield of 1926, people talk openly, and spitefully, about skin color, drawing lines not just between white and brown, but shades of white and shades of brown: Irish versus Italian, Cuban versus Spanish, and the Puerto Ricans and Dominicans against everybody.

Even the Irish are against the Irish, especially in Boston, where the movie begins. When Joe’s dad (Brendan Gleeson), a police superintendent, meets Emma, he sees a cheap girl from Cork, “the type of lassie who consorts with criminals.” (Never mind that his son is an actual crook.) Miller’s eyes flash. Her Emma is pure lightning, a beauty with a furious temper and a big grin made for dark lipstick and cigars. “I fail to grasp what you see in her,” continues Gleeson. Impossible. In her first scene, Joe shoves a sock in Emma’s mouth during a stick-up. As he wraps tape around her jaw, she cockily tilts her head up as though daring him to plant a kiss. She’s in a simple brown shirt and pants — nothing like the rhinestoned getups she’ll be wearing in a minute — but Miller dazzles.

Emma’s sugar daddy, mobster Albert White (Robert Glenister), would kill Joe in a second if he knew he was screwing his girl. You’d think Emma and Joe would keep their affair hidden instead of making out on every street corner. “We were in love and we were stupid,” sighs Joe, as though the two words mean the same thing. For Joe and Emma, they do, and when things go violently wrong in the first act, Miller kisses him desperately, her face whirling through conflicting emotions: passion, pain, fear, self-preservation. Like most gangster molls, she represents the unknowable heart of a woman. But if you freeze-frame Miller’s performance, her feelings are right there to read.

So it’s on to Tampa, where Joe swaps girls and jackets, changing his dark brown suits for tan suits, teal suits, and finally a snow-white suit so pristine he shouldn’t do anything more daring than eat mashed potatoes. (Naturally, he wears it to a shootout.) Affleck contrasts the Boston gloom against Florida’s golden potential. We’re glad to flee these depressive cobblestone streets for dirt roads, dolphins, and pretty pink sunsets. The American dream is over in New England, but there’s still space for everyone down south if they’ll get their hands dirty. Joe adapts quickly to everything but bananas. When his second-in-command, Dion (Chris Messina), offers him a taste, he’s bewildered. “It looks good?” he shrugs. He doesn’t take a bite.

The world needs another gangster flick as much as post-Prohibition America needs bootlegged booze. Affleck doesn’t make a strong case for why Live by Night had to exist, other than the fact that the original book was written by pulp genius Dennis Lehane, who also penned Affleck’s directorial debut, Gone Baby Gone. (And Live by Night won the 2013 Edgar Allan Poe Award for Best Mystery Novel over Gone Girl, which must have made Affleck think the story was a can’t-miss.) Even Affleck is aware that this turf’s been trampled flat by Scorsese, Coppola, and a hundred imitators. When the film starts, he insists he’s not a gangster at all, but an “outlaw.” That word’s too noble. Really, he’s a scavenger who refuses to join either the Irish or the Italians until the feuding dons force him to pick sides.

Affleck’s too old for the part — Joe is written to be 19, while Affleck ages him up to at least 30, and seems to be using computers to smooth out his skin. The padded maturity matters because, as Albert White warns, in the Mafia, most hotheads are dead by 40. Only supreme bosses and bit players have a shot at living to old age, and 44-year-old Affleck is playing a midlevel dealer who’s neither.

Perhaps to cut down on wrinkles, Affleck’s Joe rarely smiles or glowers. He goes through the movie in a suave stupor, seeming to want nothing more than to make it to the next scene. He’s jumping through the levels, but it’s hard to care. Even the film isn’t that interested in his dreams of building a casino. It cares more about making us like our Super Mafioso, even as Joe’s crimes get bigger. He’s a moral murderer, a guy who might kill people, sure, but genuinely adores his lovely Cuban wife (Saldana). When rival Albert White asks if his new lady is “a nigger or a spic,” Joe blurts, “She’s both,” the love in his voice turning a slur into a point of pride. (Too bad Saldana’s Graciela abandons her own crime career to become an angelic wifey in white lace dresses — the book let them stay a two-felon family.) The film steps right up to the edge of arguing that the mob is a civilizing force, Joe’s shortcut to boring suburban bliss. In this world segmented by skin color, Joe emerges as the sole progressive, a guy happy to chew out a banker who refuses to loan money to “Catholics, Jews, dagos, and Negroes.” Eventually the minority will rebel, vows Joe. Bankers like this jackass won’t survive the revolution. “I’m not going to live to see it,” he growls, “but they’re going to figure it out.” Hey, Joe, any day now.

Affleck’s quest to be a lovable leading man drains too much venom from Lehane’s book. He should trust the audience to love him anyway, or hate themselves for loving him, which gives us that fun shiver. At least the rest of the cast is spectacular, even if the center figure is a snooze. Gleeson and his Tampa counterpart, Chris Cooper’s police chief Figgis, sniff around the edges of the film for chances for their stoic supporting men to dominate the screen. As Figgis’s daughter, a failed actress turned addict turned pastor, Elle Fanning softens a role that should have claws. When she throws her arms open onstage to show off her needle scars, we’re reminded that both actresses and preachers love an audience. She could be a phony, and in the book, she clearly is. But Affleck prefers to make her a saint, even though we aren’t buying her act.

Live by Night loses energy whenever Sienna Miller’s not around. She makes this world with its showdowns about machismo and machine guns seem fresh, instead of the same old antler clashes. Still, I enjoyed the Bananas Moments when the film finds its weird flourishes. During a murder montage in which a man gets thrown off a roof, we see his hat floating down after him like a graceful comic beat. I loved a car chase in which the old engines couldn’t get past about 45 mph, especially when Joe’s clutch stalled out often enough for the cops to catch up. Sure, the Fast and the Furious series boasts perfect racing machines — give me wheels so wobbly we chew off our nails every time the hero goes over a speed bump. (Bonus: These retro tin cans were extra flammable.)

Best of all, there’s Matthew Maher’s Ku Klux Klan member, RD Pruitt, a zealot who robs bars he accuses of profiting from fornicators and bootleggers, as though stealing dirty cash off dirty businesses somehow makes him clean. “Boy’s dumb as a grape,” says Figgis, though with Maher’s pale bald head and cleft lip, he looks more like a hard-boiled egg that’s been whacked with a spoon. But dumb can be dangerous, especially when Maher’s Pruitt is a fool who thinks he’s a genius. Joe can’t negotiate with the insane. When he tries, Pruitt mumbles, “I will beat you to death,” then waits 15 seconds and howls, “I’m just playing!” presaging Pepe the Frog memes by 85 years. If there’s any surprise in Live by Night, it’s how good it feels to watch a gangster battle the KKK in the year 2017. Laws are changed, rum is legalized, Tampa’s population has tripled. But the joy of watching a white supremacist get destroyed is forever.