Creator Backlash: Alan Moore does not like the idea of the upcoming Prequel books for Watchmen, and does not want them to happen. Dave Gibbons, on the other hand, was more open to the idea, even wishing the new team of writers and artists well.
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.
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.
200 sets were used during the filming of the movie.