"Paradise Alley," opening today at area theaters, offers moviegoers the fitfully amusing spectacle of Sylvester Stallone spreading himself thin a trifle prematurely. Stallone wrote the screenplay, directed, plays one of the leading roles and even sings the theme ballad, "Too Close to Paradise," if it's permissible to describe the odd growling sound heard over the credits as singing.

Maybe there's something to be said for Stallone overreaching himself this early in his starring career. He may be compelled to take a more realistic look at what he can and cannot do after audiences exit shaking their heads over the scatterbrained mentality that seems to control "Paradise Alley." Stallone has a distinctive, funny presence and a flair for spontaneous slapstick and sentiment, but he appears to be a miserable coordinator and ringmaster.

"Paradise Alley" is a kind of "Rocky Times Three" celebrating the indomitable spirit of the obscure but scrappy Carboni Brothers, three young Italian-Americans who strive to lift themselves out of the colorful squalor of Hell's Kitchen, the legendary slum neighborhood on New York's West Side. The story supposedly begins in 1946, probably because Stallone was born that year. The period is never securely anchored. Stallone borrows motifs and cliches from so many sources that the scenes appear to emerge from a glamorously shabby never-never land.

If "Rocky" owned a lot to "Marty," "On the Waterfron" and "Somebody Up There Likes Me," Stallone's new inspirational fantasy owes as much to "Guys and Dolls," "Awake and Sing," "Of Mice and Men" and "Body and Soul", to mention some of the more prominent echoes. A Runyonesque note is especially pronounced among the snarling but ludicrous villains of the neighborhood, the Stitch Mahon gang. In addition to diminutive, sleazy Stitch himself, played by Kevin Conway with a Bogart inflection, there are his goons: Franky the Thumper, Skinny the Hand, and Rat.

Colorful? You ain't heard nothing yet. The local pleasure palaces are Mahon's Bar, a dime-a-dance hall called Sticky's Ballroom and Paradise Alley itself, a clip joint with a wrestling arena, hosted by Joe Spinell, who played Rocky's gangster employer, as a master of revels named Burp. Balladeer Tom Waits turns up among the fixtures at Mahon's as a honky-tonk pianist named Mumbles. The principal attraction at Sticky's is Ann Archer as tough-talking Annie O'Sherlock, who was the best girl of the eldest Carboni, Lenny, played by Armand Assanti, before he returned from the war with a game leg and a haunted look.

Brooding Lenny, the brains of the family, has submerged himself in a job as an undertaker's assistant. Hustling, garrulous, opportunistic Cosmo Carboni, the role Stallone reserved for himself, operates a small-time con artist and hopes to seduce Annie, who shrugs him off. Romantic that he is, Stallone plans a reconciliation for Lenny and Annie, but he fixes up Cosmo too; Bunchie, a platinum blonde whore with a heart of gold played by Joyce Ingalls, finally convinces Cosmo that she's indispensable to him.

The youngest Carboni is Victor, a gentle, simple-minded giant played by Lee Canalito, a hulking but surprisingly personable and handsome young heavyweight boxer who will almost certainly emerge as the favorite of moviegoers who give "Paradise Alley" a tolerant look. When he's not busy making his rounds on the ice wagon, Victor tries to improve his vocabulary in the company of his Chinese-American sweetheart, Susan Chow, played by Aimee Eccles.

Stallone begins the picture maladroitly and never does succeed in establishing thematic or narrative control. The opening sequence ought to be a spine-tingler: Cosmo and another neighborhood sport compete for a promised stake of $5 by racing over ten rooftops, which entails hurdling the gaps between buildings. Stallone ruins the sequence by obscuring it with the titles and stylizing it with diffused lighting, slow-motion and freeze-frames. As a result, it's impossible to feel the inherent terror and excitement of the stunt.

The story wanders around aimlessly for better than an hour while the director introduces characters, soaks up local color and gets the Carbonis romantically fixed up. By the time Cosmo gets the bright idea that Victor might be conned into a wrestling career and become a Carbonis' meal-ticket out of poverty, there's not much time left to develop a sports melodrama. In fact, Stallone more or less shoves Victor's career into one long montage sequence, during which the scheming Cosmo inexplicably turns into an unassuming nice guy and introspective Lenny inexplicably turns into a sleek, ruthless manager.

Stallone doesn't bother to explain these character switches, which have obviously occurred without benefit of obligatory documentation. For a big finale Victor, known in the ring as Kid Salami, and Franky the Thumper grapple it out over 22 grueling rounds in the rain-soaked arena at Paradise Alley. Why rain-soaked? That's never explained either. Maybe it's an open-air arena. More likely the roof leaks. At any rate, it adds an undeniable photogenic flair to the context, while complicating things for the contestants.

For all his derelictions, Stallone is a uniquely funny son-of-a-gun. "Paradise Alley" is punctuated with off-the-wall gags that are hard to resist: Stallone reaching up to pull the cord on a lamp, which falls and beans him; Stallone stalking cockroaches with a baseball bat; Stallone discouraging a pan-handler by bashing him on the head with the lid of a garbage can. The funniest single bit shouldn't be spoiled by describing it precisely, but it concerns Stallone's form of hospitality to a trained monkey that has come into his possession.

There's an outside chance that "Paradise Alley" could evolve into a cherished bad movie. Among the cast members conspicuous for moxie I was particularly amused by Anne Archer and Kevin Conway. Archer is marvelous at tough-broad insolence, like snubbing a pushy customer with the line, "Your dime's up, your time's up," and then blowing smoke in his face. Lazslo Kovacs' lighting seems to bring out a fresh, sultry glow in her large, expressive features. She's never looked more attractive on screen.

In "Rocky," Stallone created the illusion that he was physically massive. His modest dimensions become apparent in "Paradise Alley" when he stands next to Canalito, who is a head taller and looks about a yard broader - and all of it solid as a rock. At 6 feet, 5 inches and 250 unflabby pounds, Canalito is certainly the most impressive physical specimen to appear in a significant role since Jim Brown and Arnold Schwarzenegger, who played himself.

Although guys this huge seldom develop into stars, Canalito has an unusually sensitive face and appealing presence. He's a hulk with a contemplative, romantic aura. The curvature of his mouth resembles Paul Newman's, and when he smiles, the effect is pretty dazzling, because that smile has phenomenal breadth.

Stallone has returned to the safety of a "Rocky" sequel in the wake of "F.I.S.T.," a confirmed flop, and "Paradise Alley," a probable flop. I'm not sure if this means he's squandered his collateral within a single off-year. I hope not. Stallone hasn't done himself proud in "Paradise Alley." The film could still use a director, a scenario writer and someone to discourage the star from lapsing into happy-go-lucky imitations of Lee J. Cobb. Still, there's something likeable about this zany manipulator. He needs to perfect the act and postpone plans to become the whole show.