First off, here are three excellent reviews/analyses of the movie from cool people. Go read 'em.
I more-or-less agree with most of the thoughts in those posts listed above. Rather than rehash all the points already made, let me branch off into some new territory, covering roughly three areas:
1. Chad's "Russian Novel Effect"
As I get some distance from actually watching Watchmen, I'm liking it more. Whereas when I walked out of the theater, I thought it was "good, but not great" at the moment my opinion is tending more towards "Huh, that was pretty great." I'll have to see it again, and I will probably buy multiple versions of the DVD.
This is a similar mental state to what I call my "Russian Novel Effect": I hate them while I'm reading them, but love to think about them afterwards, as they unfold in my mind.)
2. Rorschach Fans, or "You didn't take the next step."
Someone on my f-list spoke about having Rorschach fans cheering and (inappropriately) laughing and hooting behind them, and they had to shush them. (Holler out in the comments, ok?)
In the viewing I attended, these sort of people were in front of me.
The amazing gore and violence caused in the fights in Snyder's movie finally made sense to me when Rorschach throws the hot grease in the face of the guy who's about to shiv him. The Rorschach fans were cheering/clapping/laughing all through this scene. This scene of someone's face excruciatingly melting off, and will eventually kill him.
Now, my mental attitude towards this went along sort of this timeline: "Breaking the glass, awesome! Grabbing the basket, cool. Kick-ass! Take that, shiv-guy! (...) OMG. That's brutal. Jebus Cripes, that guy's freaking face is melted off! That's horrible. Holy crap. I feel bad, now. Kinda sick at getting charged up in the first place."
And that realization put Dan and Laurie's alleyway fight against the KT gangers in a lot more context. Where initially, I was just thinking that Snyder was gore-ing it up because he likes that sort of thing, there's actually another layer here: the realistic (or, maybe, overemphasized) aftermath of comicbook style fights.
The thing I felt really disturbed by in the theater was that there were scattered groups of people, usually rather young (but not always), who didn't seem to reach the second part of the AWESOME/HORRIBLE two-step.
For those of you interested in such things, check out the IMdB Parental Guide for the movie here. Here's the header for the Violence & Gore section:
The violence in this movie is very bloody and graphic. While it is not shown frequently, when it is shown, the results are usually extremely graphic and brutal. Definitely not for anyone under at least 14 or 15.
3. Doctor Manhattan is a Douche.
This one's gonna ramble.
Why did he dump Janey Slater? Because she was getting old, and he wasn't. Why did he pick up Laurie? Because she was young? Doc Manhattan was having his mid-life crisis there.
Also, I think his whole "I perceive time all-at-once, not linearly" is just an excuse for him not to take any action. If everything's fated, why buck the stream? He allows himself to be manipulated by the government. He allows Blake to get carved up, and then kill a pregnant woman three feet away from him. He lets himself slip away from humanity.
Only after Ozy starts throwing tachyon-jazz around, and Doc can't see the future, and gets slammed back into linear time, does he actually get active.
IMAO, the reshaped plot that Ozy has -- make it look like Doc has blown up several major cities across the world -- is actually a better plan than teleporting a telepathic squid into New York City. (Because, in the original GN, wouldn't the world just assume that Doc would help protect them, much as America believed he'd protect them against the Russians -- not knowing he's left Earth for good?) And a really good reason this change works is because the world has seen how distant Doc Manhattan is, plus -- as far as they know -- he gives people cancer.
In other words, Ozy's plan works because Doc Manhattan is a douche, and everyone kind of knows it.
So, that's that.