Too much Tim Burton, not enough Broadway.
I'll try to be spoiler-free here, but just in case
Sweeney Todd as presented on Broadway with Angela Lansbury as Mrs. Lovett is black humor. The current film is just black. Burton just pounds and pounds and pounds it into you until the movie looks more like a bad black & white vampire flick than a Broadway classic. Johnny Depp and Helena Bonham Carter are done up in pasty clown white makeup with obscenely sunken eye sockets amateurishly done in brown and black makeup. Depp's hair features an Yvonne deCarlo Munsters white streak, and while it starts out as a nice touch, it just seems more and more cliche by the mid-point of the movie.
There is absolutely no reason for the two to look more and more Living Dead as the show progresses - they have gone from destitute to owners of two prosperous businesses, and while they have done this by nefarious means, any damage to their persons would be psychological. Physically they should be looking better and better as the movie goes on. I guess they had a meager costume budget, because neither one ever seems to change clothes.
Ditto the starkness of the set. Sweeney's barber shop must look bare at first, but by the end of the movie he's attracting some rich folks, and one would expect some elegance to creep in. Nope.
Burton also cheats a bit by using Graphic Novel style paintings of the Fleet Street rooftops with poorly overlaid lightning flashes to set the mood a couple of times. Cheesy.
Okay, this is a musical, and the question all us Broadway babies have been asking is "can either of these people sing?" The answer for Depp is "almost". He can carry a tune, but he doesn't have the pipes to carry off all of his part. He does the Richard Burton trick of speaking in tempo from time to time. Carter, on the other hand, sings well, and I thought her Worst Pies in London better than Angela Lansbury's Broadway rendition. One of my favorite novelty numbers of all time is Have A Little Priest, which the two of them do a bit too tongue in cheek. I prefer the over-the-top Broadway version, because this is the point where Todd and Lovett bond, and I didn't get much of a connection between the two of them in this movie.
Alan Rickman also proves to have a fine voice, it's kind of a shame he gets cut off so rudely. But by far the two best voices in the show are Jamie Campbell Bower as Todd's young ship mate and Ed Sanders as workhouse lad Toby, whose Not While I'm Around is stellar. Carter holds her own in the duet.
Lots of fine acting here. Besides the leads, there's the ubiquitous Timothy Spall who reprises his role in Enchanted as the Evil Sidekick. And Sacha Baron Cohen in a dual role as an overdressed and under-skilled showman barber and the Cockney blackmailer under the disguise.
But then there's the blood. Burton uses something more red than blood, it looks artificial against the stark black and white set and costumes. And he uses lots of it. There is no subtlety here. None. And it's totally WRONG because Todd is supposed to be a genius with a razor. But instead of cleanly slitting throats as such a genius would, Burton has him poking and stabbing and ripping, all to get more blood in more places. Tim, I do not think the Guinness people give a prize for that. You can stop any time now.
Other than the Burtonification foo, the movie is true to the original, and since this is not Sondheim's most tuneful epic, Depp's so-so singing was more than made up for by his superb acting. Worth seeing, but try not to pay full price. I went on a pass, but would have paid bargain matinée.