I am not much on spoofs except if it's a smart spoof like Mel Brooks did or Monty Python. From the makers of Scary Movies, Vampire Suck is a vampire spoof flick that focused more on the Twilight Saga not on the vampire genre as a whole. Though I am not a fan of the Twilight saga, I could not help but also find the movie amusing because it not just ridicule the Twilight Saga but also the its fanaticism as well.
About the casting. I never expected they can get actors fit to resemble the Twilight actors in their respective characters in a more comical manner like Jenn Proske, in her first movie and major role, plays the role of Becca and is able to spoof Kristen Stewart's Bella well as if she was her stunt double.
Although the audience can find the humor funny because of it's slapstick comedy but it will be funnier if the viewer already watches the Twilight movies specifically, Twilight and New Moon.