Sergio Leone's "Once Upon a Time in the West" was released in 1969 and bombed; when Paramount cut 24 minutes out and re-released it, it bombed again; Time called it "tedium in the tumbleweeds." It's one of those rare cases where you can say everyone was wrong. Re-released in the director's original 165-minute cut, Leone's epic western is an unequivocal must-see, just staggeringly good, the kind of movie that explodes in your head like popcorn.

The action takes place in the late 19th century, when the railroad was noisily transforming the Old West into the Sunbelt. Against this larger drama play the smaller stories of four protagonists. Frank (Henry Fonda) is a ruthless killer, a hired gun for the railroad; Cheyenne (Jason Robards) is the leader of a gang of thieves, but he has his principles; Jill McBain (Claudia Cardinale) is a New Orleans demimondaine who comes west to find her husband murdered; and a fourth, known only by the nickname Harmonica (Charles Bronson), is a drifter looking for revenge.

The three men are enemies, but there's a samurai collegiality among them; their differences are not as important as the differences between them and encroaching capitalism, symbolized by the railroad's Morton (a fine Gabriele Ferzetti), a lurching, tubercular monomaniac on crutches. The frontier is their world; civilization belongs to weaker men, Leone's gabby, doddering rustics.

The story (by Leone, Bernardo Bertolucci and Dario Argento) is self-consciously mythic, with the purity of Greek tragedy -- the perfect template for Leone's stylized vision. "Once Upon a Time in the West" is a formal masterpiece, a dazzling tightrope act of directorial style and sweep. Few have used the broad CinemaScope screen to greater effect, startling vistas and close-ups as big as a circus tent. Leone's camera runs low to ground, cranes high to reveal epic clutter, even spins at one point -- no geometry is immune.

Everything has an exclamation point. The miked-up sound track makes a horsefly sound like a DC-10; Leone uses the stark emptiness of the landscape to make his lone figures loom like redwoods, detonates close-ups in quick montage. The movie is shot with an extraordinary depth of field, and Leone loves to throw big, sharply angled close-ups in the foreground while the other figure diminishes far away -- the CinemaScope doesn't just spread across the screen, it drills straight into it. It's a sort of CinemaScope 3-D.

The scope is grand, but the mood can be playful, too: A fly lands on a killer's lip, so he retaliates by trapping it in the barrel of his .45; Leone takes a kind of childlike glee in hiding things, and then springing them on you. Ennio Morricone contributes a score of clip-clop hokum, spare minor key harmonica, and great twangy guitar licks that sound like someone playing the cables of the Brooklyn Bridge, with different leitmotifs assigned to the characters. Leone played this remarkable music on the set so the actors could mold their performances to it, and the result is the seamless effect of the silent era.

And what performances! Fonda's blue eyes are as hard as ball bearings; he draws his mouth together like a fist, and he moves with the slinky loose-limbed luxury of a lowdown panderer. And there are enough of his John Ford performances glimmering through to make him seem doubly evil -- he's some colossal Yankee hypocrite. Robards' gravelly baritone, his "heh heh heh" and the ironic mournfulness of his arched eyebrows, fill the screen with delight; he's the most appealing of romantics, the survivor who's two steps ahead because he's seen it all, but who's still searching. Cardinale adds her luscious Mediterranean charm, and the background is studded with classic western types like Jack Elam, Keenan Wynn and Woody Strode.

The great -- and only -- flaw of "Once Upon a Time in the West" is Bronson, with his flat line readings and a flatter face that holds little interest in repose, and never strays from it. Once again, he's got Charles Bronson's disease: Whenever you see him, you imagine how much better Clint Eastwood would be in the same role. Still, in a movie this wonderful, you almost don't notice. "Once Upon a Time in the West" is about the great American westerns, and how they looked to an Italian. But those movies weren't just fun to Leone -- palpably, they really mattered to him, connected with him in some fundamental way. It lends the film an urgency that transcends pastiche.

Once Upon a Time in the West, playing at the Key Theater, is rated PG, and contains considerable violence.