Darkness-Induced Audience Apathy: Everyone in the story is an asshole, and the entire plot is set up in such a way that you can see well before the end how this will end badly. At least Twilight ended well for its protagonists!
Fridge Logic: Werewolves and humans can't interbreed. Werewolves tend to kill each other over mates. Why are there still werewolves?
Interestingly enough, this is actually examined a bit in the novel. Vivian expresses more than a little frustration with the archaic and hypocritical aspects of their laws. Gabriel states outright that he feels that the loup garou have outlived their time and are merely waiting for the axe to fall.
Special Effects Failure: Just one of the feature film's problems, the werewolf transformations have the characters leap in the air, start to glow like Christmas trees before dropping down on the ground as normal wolves.