An admirable but flawed attempt at bringing the classic graphic novel to the big screen, Zack Snyder's Watchmen shows the director was probably right to repeatedly tell sources that if anyone got the chance to screw up the source material, he wanted it to be him.
The film is not terrible. It won't be mentioned in the same breath as The Spirit, I don't think. The first hour is pretty atrocious, but once the action gears up, and once Dan and Laurie are thick into their budding relationship, things get good.
The fight scenes are great. Blake's struggle for survival against Veidt is probably the singular element that supersedes the comic. We see a fighter going out in warrior fashion, yet his beatdown is still brutal enough for one to have sympathy for him. The multiple images of Sally Jupiter in his apartment also help the audience form some sympathy for the otherwise difficult-to-love Comedian (assuming they know the backstory, that is). The moments where one feels he got what he deserved don't come until later in the film.
And Night Owl finally looked like a bad-ass, maybe too much so. He and Laurie don't just immobilize, they apparently kill many of their attackers, even before they put on the capes and cowls again.
Even the final confrontation with Ozymandias is adrenalin-pumping fun. Veidt's superior strength and speed are made obvious. And I enjoyed the moment where Adrian "embraced" a final barrage of punches from Dan in a moment that was clearly changed such that the "everyman" could make the endpoint, regain some street cred, and give the audience some sense of power.
The love story between Dan and Laurie is what sells the film. But it is in what the film does not adapt concerning this story, paired with too much exposition from Laurie to explain Dr. Manhattan's powers and history, that weakens the movie.
"Do that thing you do," a perfect example of Laurie preempting the godhead of the graphic novel for the sake of advancing story, may become the "jump the shark, Fonzie!" plot faux pas of super-hero movies.
There were many moments where the violence was more excessive than it needed to be; Dr. Manhattan should have been given more weight/authority, or at least the ability to speak for himself more often, and Rorschach needn't have handled that cleaver the way he did (thanks Saw films!).
As for the acting, it was adequate. Dan and the Edward were probably best acted, then Rorschach and Manhattan. Laurie was great to look at, and the chemistry between her and Dan was probably enough to excuse otherwise deadpan delivery. Laurie's best-acted scenes were her most "emotional" ones, I guess I'll say, to be modest.
Having read the book multiple times, enjoyed the motion comic, and viewed the film, I'm happy to say that the source material hasn't been touched in terms of quality. I am worried,though, that the film will become the default accepted interpretation of the book's many subtleties and tensions, which would be a tremendous error of judgement.
Some critics like to score films with stars or thumbs. I think the symbol for Watchmen sums this one up pretty well: One smiley face, stained.