This is a movie about the hunt for a serial killer that focuses less on the killer and his victims; rather on the various characters that defined the investigation that ensued; which remains unsolved. Fantastic thriller.
This is one absorbing movie that sucks you in from the very beginning and it makes you think about the possibility of them actually catching the zodiac killer, making you forget that this one movie ends with the bad guy never being caught. And Harris Savides' cinematography is richly authentic deserves the most praise.
Finally director, David Fincher's mode of story telling here is quite wonderful especially where he used the construction of a skyscraper to explain time lapse. And as for the acting, Jake Gyllenhaal and Mark Ruffalo were really good, as Robert Downey Jr. was somewhat exhausting.
A fine mystery.