Al Capone Musical Drama Misfires : The overwrought play about the notorious gangster takes itself too seriously and lacks focus.

A musical about Al Capone, including Big Al cooing love ballads through the bars of his cell, sounds like a promising idea if it were staged in the wicked spirit of “Springtime for Hitler” (the Broadway show that’s so bad it’s a smash within Mel Brooks’ movie “The Producers”).

But staged largely with a straight face, the Al Capone musical comedy-drama “Knockin’ ‘em Dead,” at the West End Playhouse in Van Nuys, is merely bewildering. And disappointing.

This is a show you want to love. Twelve years in the making, Mike Reynolds’ score, lyrics and book feature a 25-member cast performing 60 characters and 15 musical numbers spanning song styles from 1919, when Capone first hits Chicago, until he expires in 1947 after his release from Alcatraz.

Besides coping with that large stretch of musical and gangster territory, director David Cox had to find a new space when the quake shattered his theatrical home, the American Renegade Theatre in North Hollywood, only four days before the show was to open. The production-salvaging switch to the West End has worked out fine (the seats are cushiony, but beware the cramped leg room).

Told in flashback, the show opens with a ragtime beat in a Wabash Avenue Italian joint brimming with vivid Jazz Age characters in shimmering gowns, camel’s-hair coats, fancy fedoras and double-breasted suits. There’s even a scruffy street urchin with a shoeshine box (Linzi Wittmack) straight out of a Jackie Coogan movie.

Your anticipation is high. Right off, the show looks smart, with one of the most ambitious costume designs (credited to Jessica Hall, Kathleen Demor and Butterfly Chief) you will ever see in a 99-seat theater.

But more than two hours later, the striking clothes are essentially about all that’s left to croon about.

This despite colorful acting turns (notably the well-cast Josh Cruze as Capone), a Gilbert and Sullivan-inspired courtroom trial number, and staccato bursts of gunfire so muffled and soft they amount to theater’s first politically correct machine-gun fire.

The hoods include Bugs Moran (played by the versatile Clancy Halsey, who produced the show and ably portrays five, count ‘em, five characters) and the red-headed gangland florist Dion O’Bannion (sweet-sounding tenor Bart Sumner, warbling a lovely Irish ballad before being shot and crumbling into a basket of flowers.

The production’s overriding, numbing problem is its unfocused tone, which takes itself too seriously. The show veers from a “Guys and Dolls” swagger (albeit without the humor and crispness) to ragged melodrama to misty-eyed love songs that appear ludicrous coming from Al Capone.

You get the feeling Reynolds almost loves this guy, perhaps because, according to an anecdote the playwright likes to tell, the real Capone once gave Reynolds’ mother a $5 gold coin at a cigar counter, a gesture that inspired this musical decades later.

This is certainly the most audience-friendly Capone in the history of mobster lore. Miraculously, despite the odds stacked against him, the ruggedly attractive Cruz almost pulls it off. What kills the actor (not to mention Capone) is a weepy deathbed scene played alongside Capone’s grieving wife Mae (the pearly voiced Cheryl Cameron).

If you didn’t know any better, you would swear Mel Brooks had a devilish hand in this unending deathbed scene--it’s that incredible.

Finally, there’s a sensual dance number symbolizing the Capone couple’s mutual romantic love (and sensually danced by Darlene Colaiuta and Kevin J. O’Neill). But it’s entirely played out on a stage so irritatingly dark and artsy-moody that you can’t see the dancers’ bodies.

Now if only Capone’s safe would show up, we could have a sequel.

Where and When What: “Knockin’ ‘em Dead.” Location: West End Playhouse, 7446 Van Nuys Blvd., Van Nuys. Hours: 8 p.m. Friday and Saturday, 7 p.m. Sunday, indefinitely. Price: $12 to $15. Call: (818) 763-4430.