While doing press for his upcoming action-thriller Non-Stop, producer Joel Silver revealed new details about an earlier version of Watchmen that was worked on by director Terry Gilliam and writer Sam Hamm, which was much different than Zack Snyder's version. If you haven't seen Watchmen or read the original graphic novel, there will be spoilers throughout the rest of this story.
While the producer felt that Zack Snyder approached the legendary graphic novel by Alan Moore in the right way, he revealed that the director was too slavish to the source material, and Terry Gilliam's take was a much better movie.
"It was a MUCH much better movie [...] I mean, Zack came at it the right way but was too much of a slave to the material. I was trying to get it BACK from the studio at that point, because I ended up with both V for Vendetta and Watchmen and I kinda lost Watchmen. I was happy with the way V came out, but we took a lot of liberties. That's one of the reasons Alan Moore was so unpleasant to deal with. The version of Watchmen that Zack made, they really felt the notion. They went to Comic-Con, they announced it, they showed things, the audience lost their minds but it wasn't enough to get a movie that would have that success."
Many fans believed that the graphic novel was "unadaptable" before the movie debuted in 2009, with the ending seen as the biggest hurdle. In the graphic novel, Adrian Veidt (Ozymandius) faked an alien squid attack on Earth to unite the warring nations of Earth. The adaptation, written by Alex Tse and David Hayter, replaced the squid attack with energy reactors that made it seem that Dr. Manhattan was the true villain. Joel Silver revealed that Terry Gilliam and writer Sam Hamm's take on the ending represented a significant departure from the graphic novel.
"What Terry had done, and it was a Sam Hamm script-who had written a script that everybody loved for the first Batman -and then he brought in a guy who'd worked for him to do work on it [Charles McKeown, co-writer of Brazil]. What he did was he told the story as-is, but instead of the whole notion of the intergalactic thing which was too hard and too silly, what he did was he maintained that the existence of Doctor Manhattan had changed the whole balance of the world economy, the world political structure. He felt that THAT character really altered the way reality had been. He had the Ozymandias character convince, essentially, the Doctor Manhattan character to go back and stop himself from being created, so there never would be a Doctor Manhattan character. He was the only character with real supernatural powers, he went back and prevented himself from being turned into Doctor Manhattan, and in the vortex that was created after that occurred these characters from Watchmen only became characters in a comic book."
It's interesting to ponder how the landscape would have changed, had Jon Osterman not turned into Dr. Manhattan, who is the only one of the Watchmen who had superhuman powers.
"So the three characters, I think it was Rorschach and Nite Owl and Silk Spectre, they're all of the sudden in Times Square and there's a kid reading a comic book. They become like the people in Times Square dressing up like characters as opposed to really BEING those characters. There's a kid reading the comic book and he's like, 'Hey, you're just like in my comic book.' It was very smart, it was very articulate, and it really gave a very satisfying resolution to the story, but it just didn't happen. Lost to time [...] But I did like the  movie, very much. Zack did great stuff in it!"