Ascended Fanon: The fate of Hooded Justice and Captain Metropolis has been a source of speculation owing to a couple resembling the two appearing on panel (and in focus) after their supposed demises. Dave Gibbons stated it wasn't intentional, but was far too good of a theory to refute.
Creator Backlash: Alan Moore does not like the idea of the ''Before Watchmen comics, and refused to read them or watch the film adaptation. Dave Gibbons, on the other hand, was more open to the idea of prequels, even wishing the new team of writers and artists well.
Doing It for the Art: The endless subtle hints and foreshadowing, or minor connections within the Chekhov's Army that one can find during the second read through can not be a coincidence. There are also the very detailed instructions Moore gave to the artist.
Chapter 5 is palindromic both in shape, dominant colors and focus characters note Rorschach/Detectives/News Stand/Black Freighter/Dan and Laurie/Ozymandias/Dan and Laurie/Black Freighter/News Stand/Detectives/Rorschach. It's just about impossible to notice until someone mentions it. And then you realize the significance of the final words of the chapter: "Everything balances."
Genre-Killer: It is perceived as killing off the goofier, more idealistic Silver Age type stories for some time.
Name's the Same: The second season of The Wire also features a company called "Pyramid Delivery". In both works, the company turns out to be a front set up by the Big Bad ( Adrian Veidt and The Greek, respectively).
Old Shame: Alan Moore has come to regret writing the book, given all the later comic writers who tried to capitalize on his Darker and Edgier style.
What Could Have Been: Rorschach's original costume was a form-fitting white full-body leotard with his inkblot patterns all over it. Later they threw the hat and coat on him to better resemble the Question (which had the unfortunate effect of making him look like a tattooed albino flasher) and finally dressed him up completely, leaving only the mask with the inkblots.
The story was originally meant to star the heroes of Charlton Comics that DC Comics had recently bought - Captain Atom, the Blue Beetle, the Question, etc. - but Alan Moore's story didn't mesh with DC's plans to integrate them into the revamped DCU that would follow Crisis on Infinite Earths, so he created a bunch of expies that are now arguably more famous than the characters who inspired them.
Creator Backlash: As part of his continuing vendetta with DC Comics, Moore put a hex on the film, literally. It worked as well as hexes ever do.
Disowned Adaptation: Zack Snyder once said that the best-case scenario of ever getting Alan Moore to watch his movie was that there might come one odd day where Moore accidentally puts the DVD into his player and turns it off after a second. Moore replied to this by saying Snyder was giving the movie too much credit.
In the Brazillian dub, Rorscharch is Vash, Nite Owl II is Jerry and Dr. Manhattan is Cosmo.
What Could Have Been: Jude Law was cast as Ozymandias, and was attached to the role late enough in preproduction that his likeness is clearly recognizable in the character's costume sketch◊. Law's reasons for dropping out remain unknown, and he was replaced by the then-relatively unknown Matthew Goode instead, in keeping with the idea that the story should be a bigger star than the actors involved.
Jude Law had also expressed interest in playing Rorschach.
Aside from Terry Gilliam, Darren Aronofsky, Paul Greengrass and David Hayter were all attached to direct at various points. Gilliam had a screenplay written by Sam Hamm (writer of Tim Burton'sBatman) to work with, while the others had one by Hayter himself. Much like the final film and more so than Hamm's, Hayter's treatment was pretty faithful, more prone to simplifying or cutting things out rather than changing them. However, it was set in the then-present day (2005), Laurie's alias was changed to "Slingshot" (Dr. Manhattan gives her the power to shoot energy balls), and the ending is changed even further than it was for the final film. The squid is also replaced, this time by a solar energy beam. More importantly, Nite Owl changes his mind about compromising and (barely) defeats and kills Ozymandias, since "that's what Rorschach would've done.". Well, having worked on Metal Gear really makes your mind go places. Though, according to Hayter, he actually managed to get the approval of Alan Moore concerning his version of the screenplay.
Sam Hamm's draft changes the ending even more, as instead of attacking New York at all, Ozymandias opens a wormhole back in time and uses it to kill Jon Osterman before he becomes Dr. Manhattan. This somehow has the effect of dumping the main characters into our world, and turning their timeline into a comic book. There's a reason that the fandom talks about the early screenplays not in terms of "It could have been", but in terms of "At least it wasn't."
Ozymandias' storyline ended in death in a lot of the earlier scripts, as a way of not letting him get away with his actions:
Sam Hamm version: Ozymandias is vaporized, leaving only a pair of boots behind.
David Hayter version: Nite-Owl stabs and kills him with his "owlrang".
Alex Tse version: Ozymandias is crushed by Nite-Owl's ship and bleeds to death. His body is then set aflame by the ship's afterburners as it leaves Karnak.
Viral Marketing: Veidt Enterprises had the products - Nostalgia and The Veidt Method - appear. Keene Act informational movies are throughout.
200 sets were used during the filming of the movie.
Cowboy Bebop at His Computer: It's often thought that the second-generation supergroup is called "The Watchmen". They're not called anything because there isn't really a group. The second-generation group that Captain Metropolis tried to found would have been called "The Crimebusters". It is true in The Film of the Book, though.
Reality Subtext: The sudden surge of super heroes during world war 2, decline in the late 40s and 50s, and resurgence in the 60s was meant to reflect the popularity of super hero comic books during the 20th century.