"Watchmen" is a long movie. It's a serious movie. There are occasional chuckles, but few laughs. It tries to deal with some rather serious matters. It has it's moments, and even has a couple of characters I rather respected.
But in the end, it's essentially an empty movie with an empty and depressing story whose moral is essentially a variation on "The enemy of my enemy is my friend".
It's set in some kind of alternate history, which I guess most comic books are. In "Watchmen", the famous photo of a soldier kissing a nurse in a victory celebration is turned into a lesbian kiss. The US wins the Vietnam War, though one wonders if that was a good thing. Nixon has somehow redone the Constitution so that he could be elected President for well passed the 2-term limit.
And costumed heroes have been outlawed for several years.
Probably the character the movie focuses most on is Rorschach, a 'crime noir' type of man who wears a mask that has ink blots on it that constantly shift, I don't recall really being told how or even why he chose that name and gimmick. He's street-wise, hard as nails, and while probably the weakest of the lot in terms of physical strength, tech gimmicks, or powers, he's probably also the one with the strongest character. Much of the movie is shown as entries to his journal, so is also told largely from his perspective. Comparisons to the Batman in the last two movies is almost unavoidable, considering that the actor uses much the same kind of husky gruff voice that Bale uses when in costume as Batman, but a better comparison may be with the Punisher or Wolverine.
Second in emphasis would be Dr. Manhattan. While Rorschach is a mostly normal man with a hefty amount of cynicism and rage, Manhattan is a man transformed in a scientific accident into a blue being, essentially manshaped, with powers of material manipulation, abilities to see his past and future, transportation, and others I think. Some in the movie seem to see him as a god-like being. His demeanor is calm, only once in the movie does he 'lose it'.
Although he's killed in the first few minutes, the Comedian haunts the movie by his death and by the things he did in life. I don't think it would be unfair to characterize him as a 'hero' in name only. He's at least as cynical as Rorschach but without the core of decency.
NIght Owl and Silk Spectre are kind of there to provide sexual tension, and of course the obligatory sex scene. Throw in the world' smartest man, a former hero who's gone corporate and then gone mad scientist, and that about round's out the main players.
One issue I had was with the sex and nudity. The scene with NO and SS doesn't skimp on the footage, and there are several scenes showing Manhattan's business (if you know what I mean).
The other issue I had was with the ending. It does recall "The Dark Knight", where someone blameless takes the rap for the real criminal because of some kind 'greater good'. It goes further, though, when one of them is killed so that he would not be able to tell the truth (though the movie ends with the impression that he had crossed them up on that front).
And that is one of the reason the movie ends on an empty and depressing note, because the 'peace' at the end of the movie is based on lies and manipulations, and when that is realized, nothing good can come from that. The illusion of world peace, based on the existence of a supposed common enemy, will not last.
Because the core issues have not been dealt with. The one 'hero', the smart corporate mad scientist, thinks that it's resources, particularly fuel, that is cause of wars, and that if he and Manhattan can solve the problem of energy, then the world will be a happy-go-lucky place. How that explains wars before cars, I don't know.
And the solution he does come up with--blowing up several of the world's major cities, killing millions of people, and doing it in such a way that Manhattan is blamed for it--is so shallow as to be almost laughable. Nothing is truly 'fixed', no one is truly 'changed', and while for a while the superpowers may be in agreement to stop what is the greater threat, when that is passed they will eye each other again.
It's all washing the outside of the cup, and not dealing with the filth inside it.
I think I can recommend it, though just barely. It is violent, and while that didn't bug me so much, for others it may be a problem. The nudity and sex are there, and they are graphic, and they add nothing to the story. It does give some things for thought, though, so if you can handle a bit of stuff, go for it. If not, you haven't really missed much.