For twenty years, studio after studio, producer after producer, writer after writer, and director after director took a stab at mounting a cinematic adaptation of "Watchmen," Alan Moore's highly acclaimed twelve-part comic book series. A deconstruction of superhero lore set against a real-world backdrop laden with spooky "what-if?" fantasy scenarios, Moore aimed to portray what it might actually be like if there were costumed avengers living on earth, and how the government and public at large would react to their existence. Complex and labyrinthine, violent and sexual, going off on lengthy tangents involving flashbacks and supplementary storylines, "Watchmen" has been labeled virtually unfilmable in certain circles. Maybe it is.

The picture has, indeed, finally come to fruition, courtesy of director Zack Snyder (2007's "300") and a $100-million-plus budget, but its largely sacred adherence to the source material (save for an altered finale) has suffocated the life right out of it. Being forced to cut out chunks of the finished product in order to bring the running time in at a still-lengthy 163 minutes hasn't helped. Uninitiated viewers will be left perplexed, while fans of the comic are destined to be disappointed by the corners that have been cut in bringing Moore's tome to the silver screen. The outcome, then, is a visionary motion picture more ambitious than successful. Director Zack Snyder and screenwriters David Hayter (2003's "X2") and Alex Tse strive for a lot, which is better than not striving at all, but their film is missing a much-needed soul. It is difficult to imagine many audiences walking away wholly satisfied.

In an alternate reality of 1985, Richard Nixon has been elected President for the fifth term in a row and threats of impending nuclear war have led to doomsday rumblings. A superhero squadron once known as Minutemen have been forced into retirement and seclusion, their days of glory seemingly behind them. When one of their own, the cigar-chomping Comedian (Jeffrey Dean Morgan), is found brutally murdered, vigilante Rorschach (Jackie Earle Haley) attempts to once again rally together his old pals—among them, brilliant inventor Dan Dreiberg/Nite Owl II (Patrick Wilson), slinky Laurie Jupiter/Silk Spectre II (Malin Akerman), blue-glowing nude physicist Jonathan Osterman/Dr. Manhattan (Billy Crudup), and now-wealthy businessman Adrian Veidt/Ozymandias (Matthew Goode)—and warn them of danger. Convincing them that trouble is afoot and a killer may be targeting superheroes is easier said than done, however. As Rorschach sets out to find the culprit by any means necessary, an increasingly erratic Dr. Manhattan pushes girlfriend Laurie into the arms of Dan. All the while, the planet moves ever closer to what could potentially be the apocalypse, or something else altogether.

"Watchmen" is just about as uneven as a movie can get, singular moments of dizzying brilliance arriving amidst an unfocused, lugubrious narrative and pacing that would make a turtle's crawl appear speedy. The film gets off to a rousing start with the murder set-piece of The Comedian, and then segues into a mesmerizing opening credits sequence scored to Bob Dylan's "The Times, They Are A-Changin'," wherein the history of the superheroes coincides with that of the United States throughout the twentieth century. It is all unfortunately downhill from there, with endless flashbacks of the characters' pasts doing surprisingly little to truly flesh them out as people we understand or want to care about. These talky interludes lessen the urgency of the central plot, which gets lost in the shuffle and only cursorily regains its footing for the climax set in Antarctica. As for where the superheroes came from to begin with, and what the current generation's individual powers are, it is never properly explained. The characters constantly stand at an emotional distance from the viewer and fail to become more than pawns in a chess game.

The actors do what they can to enliven their roles, but only Jackie Earle Haley (2006's "Little Children"), beyond intense as the unforgiving Rorschach, walks away completely unscathed. Haley acts his heart out—not easy to do when your face is hidden for the bulk of your screentime by a shroud of cloth—and it is a genuine treat to see such a long-underrated talent finally rise to the top of his career after years of being counted out. As Laurie Jupiter, Malin Akerman (2007's "The Heartbreak Kid") is probably second-best, her character fleshed out enough for one to sympathize at least a little with her plight as she struggles to rise from the shadows of her aging mother, the original Silk Spectre (Carla Gugino). Akerman and Patrick Wilson (2008's "Lakeview Terrace"), as Dan Dreiberg/Nite Owl II, share a steamy, explicit sex scene scored to Leonard Cohen's "Hallelujah," but when they have all their clothes on their romantic chemistry whittles out. What do these two see in each other? And what, for that matter, could Laurie see in Dr. Manhattan, who lives in a quantum universe separate from our own and has the personality of a dead fish? The love triangle between these three is plodding and undernourished.

Heavy on exposition and light on action, "Watchmen" doesn't take off as it should. Frigid from an emotional standpoint and ineffectual when all is said and done, the film concludes on an interesting, post-9/11 note that stands apart from what has come before it. That is the main trouble with the picture; it is but a series of moments, some better than others, that do not form a cohesive whole. The R-rating is certainly appreciated—bloodletting is copious, nudity is not shied away from, and the tone is very much adult in spirit—and the soundtrack is eclectic, from the aforementioned Bob Dylan to Jimi Hendrix to Nat King Cole to Nena. Additionally, Simon and Garfunkel's "The Sound of Silence" is strikingly used in a funeral scene, the Twin Towers looming large in the distance. Visual effects are first-rate, as well, and the art direction painting a world much like our own but subtly different is faultless. All of the technical and visual attributes of "Watchmen," however, cannot make up for its mechanical storytelling and lack of human connection. Long before the end, you just stop caring.