Not that there’s much that’s civilized about Gotham City under new district attorney Harvey Dent (Aaron Eckhart), who remains tireless in his crusade against the mob even as its heavies infiltrate the police department and compromise the courts. More than ever, chaos reigns: Jails and hospitals explode with alarming regularity while the city’s most notorious terrorist, with his smeared makeup and freakishly disfigured sneer, openly taunts the one man capable of restoring the peace.

That, of course, is billionaire playboy Bruce Wayne (Christian Bale), who snoozes through board meetings by day and patrols Gotham in his new-and-improved Batsuit by night. Once again, Bale brings scant humor to the Caped Crusader – he’s the strong, silent type, increasingly dour as the Joker litters his rotting metropolis with incinerated corpses – but Bale’s performance is perfectly suited to the aggressively grim tone of Christopher Nolan’s comic-book epic, and stands in deliberate counterpoint to Ledger’s macabre clownishness.

While Nolan’s second take on the Bat-franchise is less cohesive than 2005’s Batman Begins, which told a simpler story with fewer loose ends, The Dark Knight is the more thrilling and unsettling of the two. From the start, it drags us down to the fiery pits of Gotham’s anarchic hell and never lets us up for air; it is a bruising, unrelenting slice of sensory overload, a captivating spectacle as likely to dazzle the eyes as fray the nerves.

That’s a good thing, especially for those who see the film on the towering IMAX screens for which it is intended. Though Nolan is guilty of sloppy editing in spots – some sequences taper off before reaching any sort of resolution, while others are so breathlessly paced they’re difficult to follow – The Dark Knight is never less than exhilarating, a breakneck roller-coaster ride with brains and heart to match its taste for brutal theater.

It’s also a film, with its teeming cast (Gary Oldman, as the quietly dignified Lieutenant Gordon, is just as effective as Bale and Ledger) and dense, labyrinthine subplots, that begs to be seen more than once.

How does it stack up in this summer of the superhero? It is as invigorating an adrenaline rush as any comic-book fantasy could be, and a far more serious entertainment than anyone might expect. Beneath its dazzling surface, The Dark Knight is a big, brooding meditation on the moral conflict that rages even in the noblest soul, whether the put-upon D.A.’s, whose spirit is broken by the violence around him, or Batman’s, whose dark psyche is every bit as tortured as his malicious arch-enemy’s.