Really fun idea based on the theme. Love the way the characters dance to the beat; it's super stylish. The "BLEH!"s the vampires make are really funny.
The difficulty is the only real issue I have. The game starts off really hectic and only gets harder. If it started off fairly manageable and worked up to being more difficult, I think it would be a more enjoyable experience. Doesn't help that if you run out of holy water, the time it takes for it to regenerate means you'll almost definitely lose.