In short, the film is as good as an adaptation of a 12 issue, self-contained, extremely dense comic could possibly be, which makes it... a slightly better than average movie. No offense to any parties involved. I mean, David "Solid Snake" Hayter, Alex Tse and fellow Wisconsinite Zack Snyder all did the best they possibly could, but it's just not a story that works well as a movie.
Which brings me back to the people I saw it with. Of the people who did enjoy it, all but one of us had read the comic. This means that all but one of us knew what to expect. The rest? They'd all gotten it into their heads that they were going to see an action movie. To quote Rorschach, "Hurm..." An action movie? Where ever did they get that idea? Watchmen is, in many ways, the anti-action comic. It relies heavily on mood, pacing and dialogue. The movie is the same, in that respect. Well, apparently, no one told the guy who edited together all the trailers, because every trailer makes this movie look like the second coming of The Wild Bunch, except with people in costumes.
It is not that. Not even a little. But people think it is, because this movie is being market all wrong, and it's going to leave a lot of people who haven't read the book feeling deceived (which they should, because they were). From what I hear, it seems like perhaps that's what the studio wanted the movie to be (rumors of requests for edits are abound), but being true to the geeks, Snyder doesn't compromise, and stays true (as true as possible) to the source material.
Which, as I've said, is part of the problem in another way. Quite frankly, in the end you're just better off reading the book. It was conceived in that medium, it's amongst the finest examples of that medium, and you can always turn back quickly if you feel like you missed something. Of course, if you do read the book first, then you'll have all kinds of minor things to gripe about when you do see the film, but really, they're just nitpicks. In order to keep the movie watchable, it hits all the major events and plot points and gets you out of the theatre in less than three hours.
The last thing I want to say is that many of the performances leave a little something to be desired, but one performance is worth the entire price of admission. Jackie Earle Haley is, in a word, phenomenal as Rorschach. He is perfect in the role, and his performance has stuck with me since the viewing. Rorschach is by far my favorite character, and I wasn't sure if one of the Bad News Bears was going to be able to do the role justice. I'm glad to say, I was very, very wrong.