Tim Burton’s Sweeney Todd: The Demon Barber of Fleet Street reproduces Stephen Sondheim’s moody musical as a theatrically macabre vengeance play that gleefully soaks its numbers in gallons of gooey stage blood. It is a mesmerizing mess of a film that alternates its high notes with blatant missteps. Yet for all its unmistakable faults, it casts such a complete spell that I’m chomping at the bit to see it again (and again).

Where other studios might have demanded proven singers for the parts, Paramount (bravely?) permits Burton to practise extreme nepotism. The director recruits his better half, Johnny Depp, for the title role of a wrongfully jailed barber who seeks vengeance against a covetous judge (Alan Rickman) and his troll-like lackey (Timothy Spall). And the role of Mrs Lovett goes to Burton’s wife, Helena Bonham Carter. A meat-pie maker, Lovett helps dispose of Sweeney’s human victims by turning them into delectable delicacies.

Sweeney devotees hoping for a pitch-perfect rendition of their cherished stage show may be disappointed. After a strong opening that details the barber’s return to London, Burton’s musical falters – coincidentally, the drop off occurs when Carter warbles her way through The Worst Pies in London and the slightly sped-up Poor Thing. In all honesty, neither Depp nor Carter possesses a stage-quality voice. Instead, both muster emotional performances that sell the parts without selling the music. Co-stars Jamie Campbell Bower and Jayne Wisener, respectively cast as Sweeney’s protégé and daughter, are much stronger singers. The entire cast is aided by the swell of Sondheim’s full-bodied score.

It is evident, however, that Sweeney is Burton’s first stab at a musical: his staging can be as graceful as the bodies landing head first on Lovett’s bakeshop floor. And the musical lacks stage definition –­ if you are unfamiliar with Sondheim’s Broadway show, you will not grasp where the main acts divide. Furthermore, the outcome of Sweeney’s competition with rival barber Pirelli (Sacha Baron Cohen) is well telegraphed and Depp’s decision to internalize his character’s hatred makes the second act difficult to swallow.

Yet the age-old Sweeney myth plays to Burton’s storytelling strengths and fits comfortably with his usual gothic, visual palette. London’s drab, cobblestone streets (digitally created with impressive green-screen technology) are a fine contrast to the rivers of blood that flow from Sweeney’s barber shop. Burton ups the carnage as he trims the music – solos are shortened and choruses are removed to bring Sweeney in near the two-hour mark. And while the barber’s bloodlust is a tough sell that even Depp struggles to convey, Burton finds imaginative ways to colourize his demonic tale. His upbeat treatment of Lovett’s fanciful song By the Sea might be the film’s only respite from Sweeney’s gloomy mission. When it arrives, drink in the whimsy. It won’t last for long.

Sean O’Connell