Film Depends on why you like the musical
I love the original musical, but I'm not a fan of the film. It comes down to the fact that I'm not actually much of a fan of the story. I don't really connect with any of the characters. Joanna is the one I come closest to relating to, but she's very much not the focus of things. But I love the music.
In the film adaptation, the music takes a backseat, so that Burton can do... well, pretty much the same thing he does in all his films. The man is nothing if not consistent. It's not that the actors are completely unable to sing. It's that they're not at the level needed to make the music shine. And since the music is why I'm there, I spend the whole film going "Well, this is disappointing."
If you love Burton, or Depp, or Bonham-Carter, it's all there for you to enjoy. Just don't think you're getting the full potential of the music. For that, you need to look elsewhere.
Film A grim musical through and through, but that's what works.
I wasn't impressed by Tim Burton's previous foray into R-rated bloody horror in Sleepy Hollow, but I think he found his story for that tone in Stephen Sondheim's Sweeney Todd.
This is one of those awful stories that's bleak from start to finish, where at no point can anything be described as "all right". And that's why it's such a good tragic slasher story.
Todd is a man who's earned his right to revenge, having his family stolen from him by a corrupt judge and getting sent away to prison. When he returns home to disgusting Victorian London, he rents out his room again above the floundering Mrs. Lovett's pie shop, and plans to get the judge in his barber chair and under his razor. This falls apart, however, and after losing his chance, Todd goes off the deep end and wants to kill anyone. Practical Mrs. Lovett supports it as an opportunity to improve her business and get rid of his extant victim at the same time. Meanwhile, Todd's daughter Johanna is living with the judge, and Todd and his friend Anthony conspire to get her back.
The story is very good at making the viewer tense and uncomfortable. Again, the whole thing is screwed from start to finish, and I think the dark tone keeps the murders horrific while the intimate style of film helps the two leads' sympathetic and uncanny sides. Like any good tragedy, pieces pile up and fall apart in some surprising ways. The stage show was apparently more comedic, but good lord, it doesn't need to be if this film is any indication. It's great as a pure horror story.
I think the cast was pretty good. Todd is a rare Johnny Depp role where it felt like he was challenged by his part, and he rose to it. Helena Bonham Carter makes for a fascinating Lovett, being callous and deeply selfish, but with enough humanity to make her very unsettling. The rest of the supporting cast are all talented, and for a group composed mostly of inexperienced singers, you can barely tell. I do think Anthony was hard to like due to his ideal "I'll save a girl I've never met" attitude, a result of compressing that subplot for the film.
The visual style of the film is similarly heavy and colorless to Sleepy Hollow, and the grading switches nicely to infernal tones once the murders and baking begin. This style also makes a fantasy sequence pop that much more in its pretty colors. They don't hold back on the violence and gore, either, which works better for something that was a slasher story from its first source. Sleepy Hollow invented a plot and tone for a story that didn't always have it.
It is an achievement to create such a grotesque story of murder and crime and yet make it a satisfying tragedy. But this film does it, with some great music and visuals as well.