Audio problem: When Pestilence puts the bug in his mouth, we hear a crunch as if he is chewing it, yet a few seconds later he spits it out and it is not chewed up at all.
Audio problem: When Lucifer runs the comb along his tongue, you hear the clicking of the "spines", yet he is running the other side of the comb along his tongue, so you should hear nothing.
Audio problem: The mine workers are chanting "Save our jobs" in the beginning, yet their mouths never match what they are saying.
Audio problem: Upon finding Lily's dead body, there is a wideshot of Jimmy carrying her, and he is sobbing "Oh my god. Oh my god." But his lips are not moving.
Audio problem: When El Nino is laughing after meeting Satan, when the camera cuts, you can see he is no longer laughing out loud, although his laugh is still heard.
Audio problem: When War gives his first "epic" quote at the beginning of the movie, there is a period of about a second and a half when his lips are not moving, then there is a cut, and they are suddenly moving.
Answer: As I understand it, it all had to do with a spat between the director of the original Crow movie (Alex Proyas, who had "approval" of all the subsequent Crow movies) the producer of the Crow movie franchise, Jeff Most, and Miramax. Miramax eventually caved in favor of the producer and it was made into a "non-Crow entity" when Miramax reportedly signed Eminem to play the bad guy.