The Watchmen universe is rich and complex. The narrative itself is multilayered. Superficially it narrates the take of comic book like superheroes (costumed adventurers) in contemporary America (which, for this comic book becomes America circa 1985.) It narrates a tale of personal and social problems faced by people in power. However, the narrative goes much deeper than that. Like Moore has said, Watchmen was written to be understood fully only after repeated reading.
The first layer of meaning in the story comes from the way superheroes are dealt. In the comic’s alternate universe superheroes are real. The story is about the rise and fall and the rise again of these costumed adventurers and echoes, in a lot of ways how superhero comics market behaved in the US. This lends a very interesting meta-fictional character to the comic. The comic also talks about how superhero comics were marketed (in the form of PR agents for these ‘masks’) and how the franchise grows (some adventurers come out with toy lines based on their character).
A staple narrative technique of comic books is the thought bubble. The thought bubble gives comics a distinctive subjective feel in that the reader gets to know the thoughts of the character. Watchmen does away with the thought bubble almost completely. It also follows the nine panels per page format quite consistently which gives little scope for authorial intervention and adds to the objectivity of the story. The third person viewpoint is used most often in the comic. All this creates an atmosphere of objectivity and cinematic realism which distances the reader from the story.
One technique that the comic uses and that I really liked was multilayered dialog. What Moore does is this. Two or even three simultaneous stories will be narrated together in alternate panels. Each panel will have its own dialog but it will also have dialogs spilling over from the previous frames. And these dialogs make sense in the other frame too. It is as if the same dialog was written for two different stories with two very different meanings. This creates a wonderful effect of complexity which is difficult to describe.
Each Watchmen issue ends with fictional primary documents thrown in the reader’s face. One will get either the extracts from the Nite Owls biography, or newspaper clipping or even police records and personal notes. Not only is the use of different media within comics innovative, it is also adds to the realism and objectivity within the story.
The whole effect of realism and objectivity that is created within the comic adds to the poignancy of the core problem that it is dealing with – cold war and the mechanics of power. It drives the reader to connect far more concretely with the real problems around him than would do a real essay or article about the subject. The horrors of the cold war and the meaninglessness of it all is brought out wonderfully through the character of Dr. Manhattan for who humans are no more significant than termites or ants.
There is of course, loads to write about the book and loads have already been written. Google for stuff if you want to read more.