There is ambition behind "The Dark Knight Rises." Director Christopher Nolan and his collaborators distill everything that has happened in our world in the past four years — everything since "The Dark Knight" debuted in 2008 — and render it in nightmare terms. In doing so, they try, in the realm of fantasy, to tap into the fears underlying modern life.

In "The Dark Knight," the antecedent was 9/11: The vision of civic chaos and of the unrelenting, unremitting evil embodied by Heath Ledger’s the Joker expressed, in popular art, Americans’ deepest terrors in the first decade of this century. But in the final installment of Nolan’s Batman trilogy, the antecedent is the financial crisis, a much more muddled and less dramatic ongoing event. And it makes for a much more muddled and less dramatic movie … that goes on and on and on.

For about half its running time, it’s reasonably entertaining, but the other half — inevitably, the second half — is something of a slog. The movie is self-important but with little ultimate importance, and sentimental without much in the way of human feeling. But it has its moments — at 164 minutes it had better — plus Anne Hathaway, enjoyable throughout as the movie’s nicely reimagined Catwoman.

A central weakness of the sequel, when compared with the original, is the absence of a compelling, complicated villain. In place of Ledger’s Joker, we find Tom Hardy as Bane, a bald muscleman with his face and nose covered by a black leather mask. Bane is a formidable presence and as evil as they come, but he has a one-note personality, without humor or nuance. Even worse, with his voice distorted by that mask, he sounds like Scooby-Doo, which means that whenever he speaks for more than a sentence or two, he sounds unintentionally funny, not terrifying.

In the end, the heart of the movie — both in its viewpoint and its emotion — centers on the character of Catwoman, who starts the film as a socialist-anarchist anticipating the coming revolution, and then experiences a series of changes. The journey is to Nolan’s credit: It’s the first time someone actually thought through the role of Catwoman in the writing stage and gave a good actress something to play; that is, beyond the demented sexpot of tradition.

Marion Cotillard, as one of Bruce Wayne’s sympathetic business associates, and Joseph Gordon-Levitt, as an aggressive rookie cop, also make strong impressions. Others don’t fare as well. Christian Bale’s Batman has always been somber, but now the depression seems clinical. His energy is a drag on the movie, though some may like that. The movie also suffers from sequel-itis, in that everyone gets his moment, and these moments tend to showcase the characters’ deep sensitivity. For example, Michael Caine as Alfred is so worried about Bruce Wayne that he can’t seem to talk to him without getting choked up. After the first time, this becomes funny.

Moments are stretched. Every recollection must be illustrated by a flashback. Character motivations shift on a dime, and if you understand even half of what’s going on — not generally, but specifically — you’ll be doing better than most. For long stretches, there’s little that’s compelling and no point of story to resolve or hold our interest beyond a vague concern for the fate of Gotham City. After two hours, this concern fades.

But two things keep "The Dark Knight Rises" from being dismissed as overlong, overstuffed and tiresome, though it is. The first is Nolan’s visual mastery, his mix of the real and the fantastic in his vision of the modern city, and his camera moments which somehow suggest three dimensions without 3-D.

The movie’s second virtue may be disguised as a fault. In its borderline incoherence, in its operatic and yet confused rendering of the financial crisis, "The Dark Knight Rises" might better encapsulate the 2012 mindset than a movie that makes complete sense.