The problem I have, ever since seeing Fear Dot Com, is that I can no longer label any other horror movie "the worst ever made". It doesn't matter how bad a film is, and Exorcist: The Beginning is pretty bad, I just don't believe anyone will ever reach the spectacular ineptitude displayed by Fear Dot Com.
The problem with Exorcist: The Beginning is that it's just not meant to be a horror movie. The script is actually pretty good, but it's good in a Raiders Of The Lost Ark Saturday afternoon matinee, kind of a way. There's lot's of interesting plot elements that give the story weight, but none of it amounts to anything that will actually frighten anyone.
Stuck with a Saturday matinee adventure script, and orders from the bridge (ie Warner Bros. studios) to make it scary, director Renny Harlin fills Raiders Of The Lost Exorcist with as much blood, gore, and nasty subplots as his relatively limited budget will allow.
The end result is a mess.
At one point, CG hyenas tear apart a little boy. This scene epitomises almost everything that's wrong with this film: it's not scary, the effects are woefully unconvincing, and it's conceptually (if not visually) sick for no real reason.
It's a constant source of frustration that film-makers seem so intent on crapping all over the memory of classic horror films. Add Exorcist: The Beginning to the metaphorical crap heap of crappy sequel crap.