I've read the Hellblazer comic off and on for a while now and, though there was only the vaguest similarity between the film and the comic, I thought that the quality level of the film and comic was about the same. Good moments, bad moments, some nice scenes, an interesting supporting cast, a roguish and charming main character... well, that's the comic, the last one. Say what you will about Keanu Reeves, but he's always the same, monotoned voiced actor in all the films I've seen him in. I've yet to see him deliver snappy, quick dialogue and it would have been a huge bonus to the film if they had made him do this, or found an actor that could. Still, I can't exactly say I was expecting it in the film, and it's not like Keanu was any worse than he has been in previous films. The last thing I will say for people who have read Hellblazer is there's a lot more of Jamie Delano's run (the part of it collected in Original Sin) than I had heard, and there's a lot less Garth Ennis than I expected.
Now, to ignore the comic completely, because the film isn't the comic.
The John Constantine that we're introduced to in this film is a dark haired, slightly punk, slightly funeral styled dress sense man living in Los Angeles. He's not a particularly nice man, but he has a nice apartment, a young boy to drive him round in a cab, and a buddy who delivers occult relics like Q delivers gadgets to James Bond. Probably the only one of these little gadgets that is completely mock worthy is the shotgun shaped in a golden cross. I quite liked the look of the film and its gadgets in every other aspect, but this golden cross shotgun was just ridiculous, especially when placed next to a real shotgun at one stage of the film.
The problems with Constantine are simple. Firstly, the plot isn't particularly riveting or believable. By believable, I mean that here I am, sitting in a film with Keanu and Heaven and Hell and if you bring up the fact that the Devil has a son, and the spear the pierced Jesus, and I want to buy into it, but I don't. I just don't care. There's a bible in hell and the problem with this is that there's a bible in hell only because the plot requires this so it can continue. Would it have been that difficult to fashion a plot that didn't rely on so many plot coupons to explain it? I mean, there's a whole Bible there, a whole fifteen years of comics... a bible in hell just isn't very imaginative, not even for a plot device.
The other problem is, naturally, Keanu Reeves.
The problem with Keanu and Constantine is that the two don't mix. In the film, we're told the John Constantine is a selfish man, trying to buy his way into Heaven by doing selfless acts, which, naturally, is a selfish act. In film lore, Keanu doesn't have a long history of playing characters like that, and thus the audience knows that he's been screwed because naturally, Reeves is being selfless. The problem with this is when the climax of the film comes along: there's a moment when the viewer finds him/herself split along two lines, the first not believing that the character would make that choice, and the second believing that a character that Keanu Reeves is playing would make such a choice. Likewise, in the final scene of the film, you know that John Constantine would do one thing, but in the American film lore that Keanu is part of, you know he will react differently.
However, outside this two things, the film is largely enjoyable. It's stylish, and director Francis Lawrence has, despite the awful look of those trailers, given the film a life. Also, the main supporting rolls that are filled by Rachel Weisz and Djimon Hounsou, as latent psychic girl cop/damsel in distress and voodoo magician pub owner, are done quite well. Hounsou, especially, overcomes what is essentially the collection of every cliche in the voodoo magician pub owner handbook to provide a character who is still interesting to watch on screen.
The movie, however, is stolen by two performances: the first being Tilda Swinton's androgynous portrayal of the half breed angel Gabriel, and the second being Peter Stormare who, as Lucifer, leaves black tar footprints across the floor. The film is worth watching for those two alone.
In the end, Constantine won't go down as a great film, but it's a solid, fine little dark fantasy. If you've read Hellblazer, forget it when you walk in and you'll do okay, I reckon.