1. Johnny Depp is quite amazing--scary, compelling, vivid--in Sweeney Todd. So are Helena Bonham-Carter, Sacha Baron Cohen, and Alan Rickman, and various other more minor players, including the kid who plays Toby, Edward Sanders.
However:
2. Whosoever claims that the blood, gore, and throat-slitting of this movie is somehow not scary or dread-filled, is campy or played just for fun, is either way more sophisticated than I am (probably, it wouldn't be too hard to be more sophisticated than I am) or has seen too many scary, bloody, gory and throat-slitting movies.
I had to watch whole scenes/songs by not watching them. I actually thought this movie was quite powerful--but I couldn't watch the bloody parts. And not only was it bloody, it was dark. Very dark and nihilistic. Like, so dark I might be thinking about some of it for quite awhile. Or maybe having horrible, bloody, gory nightmares about it, despite what some sophisticated superannuated types may say.