This is a riveting, intellectual police investigation film, not an action thrill ride, and it is another riveting film from excellent director David Fincher (The Game, Fight Club). Even though a bit overlong, it is still gripping and intense throughout its length. The cast is uniformly excellent, especially Jake Gyllenhaal and Chloe Sevigny (wife 2 on Big Love), even Anthony Edwards in a small part, though Robert Downey does mumble his lines a bit, and can be hard to understand. This film will shed more light on the Zodiac killings than most of us know, this will likely be the definitive film on these murders and perhaps close the book. If you haven't, see ALL of David Fincher's films, they entertain and stick with you awhile.