I should have been more skeptical. The zodiac, on DVD, at Woolworths, for £4.97, when the film is still on release at the cinema? Of course it isn't the same film. The production values are good enough to make you think that it nonetheless might be, but a few things didn't quite hang together (careful - there are some sort-of-spoilers in here):
* The cheesy incidental music, which sounded like it came straight from the William Peter Blatty school for freaky music;
* The rather conventional editing and shooting style. Not entirely conventional - The Zodiac kind of hints at Se7en stylings, but in a drastically scaled back fashion, rather like a TV Movie trying to "do" Se7en. (Obviously, the directors weren't to know that David Fincher would subsequently dramatise the same story, so they can hardly be blamed for attempting to ape his style);
* The "nutmeg" in the script represented by the Detective's son, his relationship with his mother, a teenage girl and the case itself, which gives every indication of leading somewhere, but evaporates without trace;
* The fact that, on 87 minutes, without warning, the film suddenly stops dead - nothing resolved: not the murders, not the detective's relationship with his boss, wife, son or the killer, not the "your wife and children are vulnerable" subplot, nor even the motivation of the killer (who had graduated from son-of-sam style killings of fornicating sweethearts to indiscriminately murdering of taxi drivers and whose MO had changed from shooting, to stabbing, to shooting *and* stabbing). One gets the sense the producers ran out of money.
This is a competently shot, acted and edited picture, but the screenplay is just hopeless. There is no story arc (it's basically "some innocent people get shot. The killer taunts the police. He never gets caught", which would almost be ok if there were a character arc, but there's not one of those either. The characters' relationships just deteroriate, a bit, but never fatally.
Some (possibly unintentional) humour at the death, when a letter from the Zodiac is read out in which the Zodiac brags that his exploits would make a good film (well, maybe, but as this effort shows, not necessarily!) wonders who might play him in the movie: In this treatment he remains a silhouette throughout. Never mind.