This movie deserves two separate reviews. The first is for fans of the the award-winning graphic novel, a dense, complex, challenging story of superheroes and costumed crusaders with lives that are messy, dysfunctional, and bleak.

You will be very satisfied with this film. Director Zack Snyder (300) is a fanboy who is passionately committed to the book and in essence and detail he really gets it right. The visuals are stunning, especially Night Owl’s flying “Archie,” and he has meticulously realized the vision of writer Alan Moore (V for Vendetta). Although Moore famously has had his name removed from the film because he does not believe that the story he designed to be told in panels on a page can be translated to screen, I think even he would agree that this is a much more sophisticated and faithful adaptation than “V for Vendetta” or “The League of Extraordinary Gentlemen.”

While there are moments that reflect Snyder’s understandable nervousness in meeting the demands of the graphic novel’s devoted — sometimes obsessive — fans and one serious weak point in the flat performance of Malin Ackerman as the story’s most significant female character (both Silk Spectre characters, mother and daughter, would appreciate the irony of apparently casting a performer solely for her looks to play one of their roles), overall the film faithfully and successfully grapples with the multi-layered storyline and the fascinatingly flawed characters.

And now for people who are not familiar with the book:

Don’t expect “Iron Man,” “Spider-Man,” or “The Dark Knight.” In fact, as darkness goes, this makes “The Dark Knight” look positively sunny. These are not people who get bit by a radioactive spider or come to earth from an exploding planet. Most of them have no special powers. They are just adrenaline junkies who like to get up close and personal with things that are very dark and disturbing, sometimes for reasons that are very dark and disturbing. And this is a dark and disturbing film, a hard-R with sex and violence that is just this side of an NC-17.

If you think all of that relates to the fact that it takes place in a slightly tweaked alternate world in which Richard Nixon is still President in the 1980’s, then you are beginning to get the idea.

And just to give you some further sense of how fully-realized the world of Watchmen is, the graphic novel, which was on Time Magazine’s list of the top 100 books of the 20th century, is filled with all kinds of artifacts and ephemera, newspaper clippings, excerpts from a memoir, and a separate story about a boy reading a comic book about a pirate. Snyder has separately produced some of this material and it will be integrated into the film when it comes out on DVD.

One of the highlights of the film is the opening sequence set to Bob Dylan’s “The Times They Are a-Changin’,” bringing us up to date and provide some history and context. The song has, like everything else in the film, at least two meanings. The first is that intended by the song, the upheavals of the 20th century. The second is Moore’s cheeky parallel adjustments. In one quick shot, a female character replaces the sailor planting a kiss on the nurse in the iconic V-J Day photo by Alfred Eisenstaedt.

Years before, there was a group of masked crime-fighters called The Minutemen. One was the Comedian (Jeffrey Dean Morgan), a cigar-chomping, heavily-armed tough guy who sports an ironic (and anachronistic) smiley-button. It is his murder that sets off the story, and he appears in flashbacks that illuminate the past and present. The Comedian is the only Minuteman to belong to a sort of loose successor organization, The Watchmen. But caped crusaders have been outlawed by the Keene Act, and they are not working together any more, at least not officially. Former Watchmen members have gone on to other things. Ozymandias/Adrian Veidt (Matthew Goode), the most intelligent man in the world, now heads up a global corporation. Dr. Manhattan (Billy Crudup), once a scientist, was turned into a blue creature with the appearance of a man but with power over time and space. When he needs to think, he hangs out on Mars. His girlfriend is Laurie/Silk Spectre (Akerman), a second-generation crime-fighter. Her mother, the first Silk Spectre, was one of the Minutemen. And then there is Rorschach (the superb Jackie Earle Haley), named for the famous ink-blot test that inspires his mask. As in “V for Vendetta,” these characters all struggle with ends/means issues, but in Rorschach’s case, the line between justice and vigilantism is especially permeable. Everyone is compromised. The good guys are not all good but, even more intriguing, the bad guys are not all bad.

The range of perspectives on how to confront injustice, the moral compromises, and the personal and professional demons of the characters are set in the political context of an escalating nuclear arms race. Do we as a society exploit those who are damaged in ways that are convenient for us, allowing them to do the dirty work while we have the satisfaction of moral superiority? Can you fight bad guys without becoming one of them? Is being smart the same as being wise? Who watches the Watchmen? Does knowing the future reconcile you to it? What is the mask and what is the face? And what does it say about us that we call this entertainment?