If there's a difference between bad dreams and nightmares, Quentin Tarantino has not only found it, he's put it on film.

The result is From Dusk Till Dawn, a post-modern mishmash of Scarface meets Night of the Living Dead, with a pinch of Pulp Fiction for good measure.

Not surprisingly, the action is ominous from the outset.

A flatbed trailer zooms down a dusty desert road, passing a police car headed in the opposite direction. The camera latches onto the car and follows it to Pete's Liquor World. Inside, Pete is keeping cool, or as cool as he can, given that it's 100 degrees in the shade and his only customers are two fugitives from justice and their most recent hostages.

The fugitives have cut a deal with Pete: He doesn't tell the Texas Ranger they're in his store, and they won't cut him into little pieces.

Suddenly the Ranger is dead on the floor and Pete is a ball of flames. Fugitive No. 1 felt betrayed so he unilaterally canceled the ceasefire. Good-bye Scarface. Hello Night of the Living Dead.

Plotwise, From Dusk Till Dawn is pretty straightforward. It concerns two brothers, Seth and Richie Gecko, who pick up where the Holocaust left off. Before the film has even begun, they've committed a jail break, a bank robbery and eight homicides. And the day is young.

Seth (George Clooney) is the brains of the outfit. He knows what to do even when he won't do it. Richie (Tarantino, who also wrote the script) is the resident psycho, a rapist whose only hold on reality is the orders he gets from his brother.

Their goal is simple: Get across the border to Mexico. The plan is just as simple: Hitch a forced ride with Baptist preacher Jacob Fisher (Harvey Keitel) and his children, Ernest Lui and the flannel-clad Juliette Lewis.

All goes reasonably well for the extended family 'til they get to their rendezvous, a topless bar called "The Titty Twister." Don't flinch; it's just Tarantino at his most subtle.

That's where both Tarantino the actor and Tarantino the screenwriter get into trouble.

Tarantino the actor has to fight off a D-Day invasion of the Undead, while Tarantino the writer has to face the ironic twist of post-modernism: It grows old fast.

Tarantino has a lot of fun poking at Hollywood cliches and satirizing over-the-top action films; Richie peeping through the bullet hole in his hand; Seth citing Peter Cushing as an authority on vampires; Seth and Richie arguing about how you handle hostage situations while the liquor store blows up behind them.

My favorite touch is the TV report that includes a homicide-count graphic, broken down by categories. At moments like this, Tarantino is on the money, and From Dusk Till Dawn has something to say. It's like rolling Airport and Airplane into one film that parodies itself even as it unfolds.

But with its overlong battle-royale climax and unhealthy obsession with Richie's unhealthy obsessions, From Dusk Till Dawn clearly puts more effort into being part of the problem than part of the solution. And revels in it.

Its fans will no doubt point to the witty dialogue, intense acting, masterful special effects and rockin' score, which features, among others, Stevie Ray Vaughn. Personally, it gave me nightmares. And bad dreams.