I finally saw this movie, and can happily report that it has a great many angles worthy of analysis! But to keep this post Very Short I will address only one point, which I trust will not really be a spoiler. And this key point is, the omission of the squid.
You don’t know about the telepathic terror squid? Go read the graphic novel — it is not in the movie. My contention however is that it is a better movie, a better story, without the squid.
The idea that a story ought to be unified is a concept that goes all the way back to Aristotle. Like machines and musical theater, a story should have as few parts as necessary to keep it upright. (There is another whole class of things, like circuses, gardens and cooking, in which more is almost always better — almost everything on a plate is improved with curls of dark chocolate, for example — but I am valiantly trying to keep this thing Short.)
Losing the squid in the transition from graphic novel to movie has improved the story strength of Watchmen considerably. The core plot problem — saving the human race — can now be solved within the circle of the members of the Watchmen, without dragging in an alleged extraterrestrial with tentacles. The inescapably laughable bits — murmur it aloud to yourself, telepathic terror squids, and smile — vanish away. Logical conundrums, like the difficulties that the unlucky Adrian Veidt would inevitably face trying to foist off a cephalopod onto a scientific community armed with DNA analysis, are gone. And now, we have an ironclad reason for Dr. Manhattan to take off for another galaxy, a point that was always weak in the print version, where it was attributed to Feeling Remote About Humans. (Reason tells you that this problem would not be solved by removing yourself from all humans; the solution would be to join a bridge club, line-dancing class or yeah, maybe even a superhero team.) When problems are solved by the change, it is the right change to make.
The story is tighter and more focused for lack of the squid. And anything that can be removed from a story really should be removed. Fiction is like fashion models — there is no such thing as one that is too lean and taut.