Overall, I liked it, but I'd say it's got a great number of flaws. Yes, I have read the comic and it's by far my favorite piece of any media I own.
The Good:
The opening scene with The Times They Are a-Changin was one of the best openings to any movie I've ever seen. It clearly introduced us to the Watchmen world, and gave us a great deal of the back story that was only revealed in the back of the comics. The music fit the scene very well, but was one of the only times in the movie I felt that.
Rorschach was executed perfectly, and every minute with him felt right. I even liked the chopping of the one guy's skull, but I still would've preferred the original part. I would've also liked to have heard more voice over by Rorschach.
I thought the casting for Nite Owl couldn't have been done better. The scene with him standing naked looking at the Nite Owl costume is probably one of my strongest memories of the comic, because it is so iconic of the watchmen universe. A chubby ex-hero looking at his "powers." Honestly, all of the casting choices were right on the money with one very minor exception I'll mention later.
The Bad
I felt there was a lot of work done on this movie to make it accessible for all kinds of people, but it failed miserably. The entire plot is lost on anyone who isn't a fan of the comic. They did not make a good movie, they made a good fan service. At 3 hours, I can't imagine anyone who didn't know about watchmen to come out of that movie liking the story.
The music was stupid. Hallelujah during the 5 minute sex scene? The music when Manhattan is killing in Nam is hilariously retarded. It's like the music director went through the top 10 most used songs in movies and made sure each one was in Watchmen for all of the non-watchmen people. This completely removed me from the magic every single time they did it. The only successfully used music piece was at the beginning.
The major loss in the translation between comic and film is the subtleties. I don't think that these things would've been difficult at all to incorporate, either. The TV during the impotence sex scene is very important in the comic: In the movie, the scene is about them screwing. The superimposing of ideas onto other ideas was what made watchmen so completely amazing. They do some of that, but only in the most obvious ways. The ZOOMING IN on the sign out in front of old nite owls house was stupidly obvious.
On the above point, I still think I enjoyed the comic more because of things like the pirate comic book being a direct allegory for the events in the story. The characters around the newsstand also made the ending of the comic resonate and make more sense. We saw people we understood and cared about die for no reason in NY. Their arguments and problems were what realized the actions of the heroes as important. I also missed the "idea" of the monster and his creation and the point of there being an alien attack. The Dr. Manhattan idea is far more logical for the film, but it makes it a story about him and the God complex, and not about the compromise a hero must make in order to save people.
The makeup on all of the "old" people was terribly bad. Just stupid bad. I spent all of the time looking at the glue on the edge of Silk Specter's mom's forehead. She wasn't a very good actress, either. Manhattan's old girlfriend was equally poorly makeuped. Considering how polished everything else was, this stuck out like an ugly ugly sore.
They tossed in things that were just stupid. Why did time freeze when Silk Specter was in the burning building? It just felt contrived and illogical to toss in. Like the director needed to use his staple slowmo from 300 in order to tell the story. There were other moments that I can't quite remember now, but it very much felt like lots of things were done just to make the movie more action-packed or exciting. This bothered me greatly.
I am highly anticipating the box set DVD release of this film, as I'm willing to bet there's a lot of the scenes I really want to see. If there isn't an edited together pirate/newsstand/properending I'll edit one together myself, god dammit.
I want to repeat this outside of the spoilers: The intro is so god damned well done, I just saw it again.
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