HELLBLAZER is a great comic, but the way they approached the movie has a lot of us up in arms. For some real rants on the subject, I recommend visiting Brian Keene's message board (
http://www.briankeene.com). While it may be a decent movie (and from the preview, I'd say it hits a lot of notes that I love), the major problem is that the main character bears next to no resemblance to Constantine as he appears in the comic. For one thing, in HELLBLAZER, Constantine is English, blonde, addicted to cigarettes, and an extremely unpleasant person who manipulates the people around him to move his own agenda forward. Great stuff. The character in the film seems more along the lines of Clive Barker's Harry D'Amour, a burnt out detective in the middle of an all out war between Good and Evil. It's a great archetype and I've touched on it a few times in my own comics, but it doesn't really get to the heart of the pre-existing character.
Of course, maybe that's just how they're selling the movie. Who knows? But on the surface, it doesn't seem to capture the character in any meaningful way. And they made him American, for God's sake!!
--Matthew