first off keep this thread spoiler free for people who havent read the book, or at least use spoiler tags, I already had to edit one post.
onto my thoughts!
I saw it last night, and having adored the book, i went in with the realistic expectation that I could not hope for a movie to be as good as the book. Once you get around this fact, I found that I really enjoyed the film. The film at some points is so true to the book that it made me giddy. The gore was often fairly liberal, and I think could have been toned down a bit, and the stop motion was a little overdone (although it didnt totally detract from the movie like it idid in 300). Also, I do have to say some of the characters lacked a little of the fucked up personality they had in the book (Laurie). The Comedian was stellar, Rorschach was stellar, Manhattan for the most part was steller (blue penis aside). Nite owl was ok.
I thought as a film adaptation it was done as well as could be done, and thats a huge compliment. They obviously omitted things, but those are the things you have to go in expecting they will omit (the newspaper stand stuff, the backstory of the black guy, etc) as the movie can only be so long. Many people complained about the length but I think it was necessary. As a Holywood version of the most celebrated graphic novel of all time, I think it did well to combine character development, narrative, action scenes, special effects, soundtrack (amazing). At some points it did try to bite off more than it could chew, but most things were linked together and someone who has never read the novel should be able to still follow and enjoy the film (albeit not half as much as someone who has).
Onto the flaws lol, and there is only one noticeable one imo, but my god.
The ending was terrible. They changed it from the book, and the books ending was not even that good to begin with. But Jesus Christ they made it worse. At one point some guy in the crowd yelled out "THIS IS BULLSHIT" and people got up and left with 5-6 minutes left in the movie (after Nite Owls NOOOOOO lol how terrible) just because the ending was so bad. Way to ruin it.
So basically the first 2 hours and 20 minutes are great, great cinema, both as a movie and as being true to the book. A great adaptation of a great book, sure to entertain. But wow the ending can just go fuck itself.