During an interview to promote his new The Imaginarium of Doctor Parnassus, Terry Gilliam revealed what he thought about Zack Snyder's take on the classic graphic novel Watchmen:

It got trashed, but there are great sequences in there, but the overall effect is kind of turgid in a certain way. I started putting it down to… you know, in the comic book, or graphic novel… They're still comic books to me (laughs)… It's like the Comedian's coffin is going into the grave with the stars and stripes on top of it and reading it in the comic book it's three panels, boom, boom and boom. On film "hhhhhhhhhhhhmmmmm…"

The pace is wrong. I was glad our version didn't get done, the one that Charles McKeown and I had wrote, because we had reduced it down to about two hours and five minutes I think and we lost so much. Comedian was cut down to next to nothing. So (Zack Snyder) did a good job, but it just felt… I also thought The Incredibles had kind of fucked it for him... [S]o much of that material had been in a quarry that everybody had been digging goodies out of and suddenly you get lost. I think Watchmen really bothered me, because I thought it should be better. It was all there. It looked right, but to me it was pace. It didn't have pace. It needed a bit more quirkiness in there. Dr. Manhattan was getting boring, frankly, and then Ozymandias by the end I thought "Oh, come on!" They lost me by the end, frankly, but it was certainly looking better than what I was going to do! (laughs)

Source: Ain't It Cool