Quentin Tarantino has made his heist-gone-wrong film, his post-modern crime jumble, his hazy Elmore Leonard adaptation, his revenge fantasy, his war story, and now, unintentionally, his disaster film.

For “Django Unchained,” the director’s long-awaited slavery epic, is, in Tarantino terms at least, a disaster – a waste of time, talent and money. It is not just the larger-than-life director’s worst feature (I’m leaving out the god-awful “Death Proof”), but 2012’s most crushing cinematic disappointment.

It will, you can be sure, draw many raves. It already has.

But as a filmgoer who found seeing “Pulp Fiction” at age 14 a life-changing experience, and who considers “Inglourious Basterds” one of his favorite films, it is shocking to write this: It’s a bad movie. Period.

That’s especially upsetting because, typically for a Tarantino creation, it is sprinkled with moments of brilliance.

But things are amiss from Scene One. As the film begins, we see Django (Jamie Foxx), a slave in chains, marched through a desolate landscape – clearly, we’re in Sergio Leone territory, right down to the Morricone, although the spaghetti Western “Django” is the more literal connection. (Its star, Franco Nero, has a cameo here.)

Django and his captors are approached by a bearded German “dentist” on a rickety wagon, and this charismatic figure, Dr. King Schultz (Christoph Waltz), is seeking one man: Django. Schultz is a bounty hunter and wants Django’s help to find men whose faces he has never seen, but Django has.

The scene plays out slowly, ending in the expected blood-burst, but it feels forced, unlike the similarly lengthy opening of “Basterds,” which also featured a smooth-talking Waltz. Sadly, this sets the tone for the film.

The first hour – “Django” is a stunning 165 minutes, longer than “Lincoln” and even “Les Misérables” – is by far the film’s finest stretch, as Schultz and Django bond, and begin their search for Django’s wife, Broomhilda.

Broomhilda is owned by the colorful, and horrible, plantation owner Calvin Candie, played by an oily and effective Leonard DiCaprio. Surprisingly, things turn sour upon his introduction, and our arrival at his estate, “Candie Land.”

It is not Leo’s fault, but from here on, “Django” descends into the grotesque – “Mandingo fighting,” two of the more horrific deaths of Tarantino’s career, and, eventually, gunfight upon gunfight.

There are, of course, moments of great Quentin-ian wit, gorgeous cinematography, a killer soundtrack (in a perfect world, Rick Ross’ “100 Black Coffins” would score an Oscar nod). And, of course, there is the cast.

Foxx has never been better, capturing Django’s pain as well as his weary optimism. He makes the character’s march toward Broomhilda undeniably cathartic. But unsurprisingly, it is Waltz who steals the show. His Schultz could be Hans Landa’s great-grandfather, and the performance equals his Oscar-winning work in “Basterds.”

DiCaprio is fine as the dandy plantation owner, but never as memorable as he should be; Samuel L. Jackson, as Candie’s paranoid house slave, and Don Johnson and Dennis Christopher make droll contributions. (Kerry Washington as Broomhilda is saddled with the film’s most thankless role.)

But it all gets old. And it gets dull. And even though it is surely accurate, the unrelenting brutality, and the near constant use of the n-word – there are times when it seems to be in every other sentence – make it even more unpleasant.

“Django” features some of the most violent, unsettling scenes of 2012, and of course, depictions of slavery should be this repellent. But the film isn’t good enough to justify the scenes.

Here Tarantino, that proponent of exploitation cinema, is exploiting the darkest segment of American history for the sake of ... What, exactly? What does “Django Unchained” add in its view of slavery?

Nothing, because its director is far too interested in how the film plays off of other films than in making a real statement of any substance. He is a masterful filmmaker, but he falls victim to his worst tendencies, including casting himself in a distracting role, complete with a ridiculous Aussie accent.

The world’s most well-known lover of trash cinema has now moved into actually making trash cinema. What he will do next is anyone’s guess, but I can’t wait to find out if “Django” proves to be the nadir of his career. For the sake of the world’s cinephiles, I sure hope QT has hit bottom.