The Dark Knight is rated PG (in Canada), which gave me reason to believe that the film wouldn't be as DARK as I'd hoped. However, through Chris Nolan's brilliant direction, the violence in the film is fleeting, but at the same time, intense. For example, The Joker is giving a speech to someone before he cuts the person's mouth, as soon as he slashes, it cuts to the opposite angle. It works, though it may be disappointing to the fans who want to see a more bloodletting Bat flick.
I have to say that Harvey Dent's transition from straight D.A. to twisted Two-Face is well written, looks amazing, but is slightly, and only slightly underplayed by Aaron Eckhart. Maggie Gyllenhaal is a lively improvement over the dull Katie Holmes, and Garry Oldman is an adequate Gordon, yet again. I enjoyed the extra screen time allotted to Morgan Freeman's character, Lucius Fox. He plays a role in one of Batman's early missions, and in the climax of the film as well. Christian Bale's performance is good, and just that, and as for the critical complaints about his raspy Batman voice being distracting, to me, he sounds just like Batman should, so no complaints here.
The action sequences are appropriate to the story and are never overblown or unnecessary. There is a growing appreciation for practical film making, where in the past decade or so, we've been so inundated with CG rendered action that we really like it when something is filmed for real. What CG there is in the film is not obvious, even the complexity Two Face's disfigured half is visually stunning.
The Dark Knight is the best comic book movie ever made, far from a masterpiece, but worthy of first place in it's genre. It blends elements of a stellar crime drama with elements of a good comic book movie, with a cast that takes the material just as seriously as the script portrays. For the fans who love Batman Begins, this is the sequel you've been expecting, hopefully the sequel that you'll love.