I don't think I was alone among David Fincher's fans in hoping (if not expecting) that Zodiac was going to be The Godfather, or at least the Goodfellas, of serial killer movies. Instead, Zodiac is more like the All the President's Men of serial killer movies, which I found somewhat disappointing.
It seems to me that in most of his movies, all of the interesting stuff is happening on the surface - whether through visuals in Seven, through tightly controlled set design and staging in Panic Room, or spoken directly to the audience through the screenplay in Fight Club. There's not much subtext in Fight Club, because Edward Norton's voice-over lays out almost all of the major themes of the movie for us and Fincher and screenwriter Jim Uhls illustrate these themes in a relatively literal manner.
I think these movies are all superficial, but I don't really mean this as a criticism. Rather, I'm most interested in what's already there on their surfaces, which are densely packed with information and, in the case of Fight Club at least, ideas.
(Not surprisingly perhaps, I think the best parts of Chuck Palahniuk's early books are their essay-like sections that give Palahniuk a chance to rant directly to the reader about the state of contemporary culture. But their "story"-sections seem to me to be half-formed).
My problem with Zodiac, then, is that, on the surface, it's a couple of extremely well-directed set pieces recreating the killings, surrounded by a decent journalism/police procedural. But that's kind of all it is and it never quite convinced me why I should really care about this case. I never got the sense that the movie had anything to say outside of itself, in the way that, say, Fight Club deals with a whole bunch of "issues", and I also never got the sense of why the Zodiac investigation itself deserved this kind of elaborate, expensive dramatization. I mean, All the President's Men deals with an event that shook the country and whose effect is still being felt today.
Actually, the procedural stuff went over well enough while I was watching, but on reflection, it seems like the movie dropped the ball with lots of little nuts-and-bolts stuff. I'm tempted to read the books that it's based on, not so much because I'm interested in the material, but because I bet that they clear up some of the points that the movie passes over.
And Fincher and screenwriter James Vanderbilt don't do anything with the Zodiac murders, like, for example, putting them in a larger context and exploring our fascination with unsolved cases like this, as Alan Moore and Eddie Campbell do with the Jack the Ripper killings in From Hell.
Nonetheless, I thought the movie was pretty engaging and interesting for the first two hours. But then the procedural stuff ends and it turns into a movie about a lone Robert Graysmith looking for the truth. These scenes at the end aren't bad, per se (although one of them - when he goes to visit the manager of the silent film theater - is badly misconceived), but they're pointless. I never really got a sense of why Graysmith let this obsession almost ruin his life. One solution would have been to have a more critical take on him, in order to get at why people become fixated on serial killers. The movie is based on his books and he was involved in the production of the movie, so it's kind of strange that the movie never bothers to get into what drew him to this story in the first place.
Given the same material, someone like Hitchcock or De Palma would have (I think) tried to get underneath it: to suggest what really drove Graysmith to keep at the case even after everyone else has given up because the answers that the screenplay offer are kind of stock.
Still, though, it's a well-made movie and the murder sequences are very creepy and very different in style and feel from anything else Fincher has done. I'll probably see it again when it comes out on DVD, just to check whether or not there's more going on there than met my eye.