Exactly one year after earning near-unanimous raves for its production of Stephen Sondheim’s “Into the Woods,” West Boca’s adventurous Slow Burn Theatre Company has decided to tackle another ambitious Sondheim masterpiece: “Sweeney Todd,” that family show about revenge, rape, cannibalism and a throat-slitting demon barber. In his curtain speech on opening night last weekend, director/choreographer Patrick Fitzwater called it “The biggest show I’ve ever mounted.” I believe him; “Sweeney Todd” runs two and a half hours and contains 27 credited songs, many of which constitute a medley of numbers, sometimes sung simultaneously. It is not an easy task even for Broadway, and while I commend Slow Burn’s braveness, its production is not quite ready for prime time.

You probably know the story: Matthew Korinko plays Sweeney, the barber-turned-prisoner who has returned to his London stomping ground to exact revenge on the vindictive judge who banished him to exile and stole his wife and daughter away from him. His only friends are Mrs. Lovett (Karen Chandler), an incompetent baker who strikes a unique business proposal with Sweeney; and Anthony (Christian Vandepas), a young sailor who will soon become smitten with Sweeney’s daughter Johanna (Kaela Antolino), who is still languishing under the care of the corrupt and lustful Judge Turpin (Shawn Wayne King). In their attempt to discretely kill their way toward Turpin, Sweeney and Lovett take in their own ward, an innocent huckster’s assistant named Tobias (Bruno Vida), who will ultimately prove Sweeney’s downfall.

It’s a good thing I knew this story going in, because if not, I would be hopelessly lost during most of Slow Burn’s first act. The show’s sound design is remarkably poor, crushing the show’s momentum before it even gets under way. On opening night, certain microphones were so low that the singers’ vocals were barely comprehensible, and much of the dialogue sounded muddled. Sondheim’s masterly wit hardly translates when nobody can understand it.

Other times, the actors themselves are the problem, as when they can’t keep up with Manny Schvartzman’s musical direction; on opening night, it often appeared they were rushing through the numbers to get through them on time. Karen Chandler channels the correct kooky spirit for Mrs. Lovett, but she could have used a (better?) dialogue coach, because her British accent is inconsistent. King’s performance as Judge Turpin is all affect and no conviction, failing to instill any of the scorn and creepiness his character is supposed to engender; when he limply strokes his back with a whip in the self-flagellation scene, it comes off as comic, not disturbed. Vandepas and Antolino have lovely voices, and they sing well together, but as actors, they’re ciphers going through the motions. I haven’t even mentioned Ann Marie Olson, as the Beggar Woman; her amateur mistake at the end of the play undercut a tragic plot twist and resulted in derisive giggles from the audience; afterwards, probably frazzled, she missed a cue.

These are all individual failings, but the big-picture problem is this: Fitzwater’s cast struggles so much to simply get through this difficult material in one piece that they fail to connect emotionally, a problem that even plagued Korinko, a Carbonell-nominated actor as formidable as anyone on the Slow Burn stage. There wasn’t enough anti in his antihero; I wanted more menace oozing from his pale countenance.

I don’t want to dismiss this production entirely. Some of it is quite lovely, especially the intimate numbers between two characters – “By the Sea” and “Not While I’m Around” are both terrific, falling in a second act that is solidly more polished than the first. As Tobias, Vida is the show’s great discovery, exhibiting a flawless comprehension of his character and realizing both his initial innocence and his devastating breakdown. And Ian T. Almeida’s set design feels like a 3D Expressionist goth-scape brought to life by the slicing chiaroscuro lighting of Lance Blank. All of these elements give me hope that in this weekend’s final productions of Sweeney Todd, redemption may be possible for the rest of the show; let’s hope that the kinks, which should have been ironed out before opening night, will have dwindled to a minimum.

“Sweeney Todd” runs through Sunday at Slow Burn Theatre at West Boca Performing Arts Theater, 12811 W. Glades Road, Boca Raton. Tickets are $35 adults, $30 seniors and $20 students. Call 866/811-4111 or visit slowburntheatre.org.