Millions of faithful fans have kept Larson's work alive, and of course there's interest now in anything Larson wrote beyond Rent. There isn't much, but there's Boom!

It's a chamber-sized show, with a small band and just three actors—one plays Jonathan and two others (one female, one male) are various friends and family. Boom! depicts Jonathan's life as a kind of Faustian temptation. Our hero, about to turn 30, aspires to change musical theater forever. To this end, he's willing—mostly—to work hard in a grimy, tiny New York apartment (apparently urban bohemia was a favorite Larson trope). Yet he's pulled in other directions—by girlfriend Susan, who yearns for bucolic middle-class-ness in Cape Cod; and by Mephistophelean corporate friend Michael, with his shiny new apartment and Beamer with leather interior.

There's not a lot to the script, though Larson gets off a few good lines. The musical numbers are of greater interest, but the circumstances color our perception. Boom!, written in 1990, has assumed cult status in the wake of Larson's death, but it's a piece of relative juvenilia (he was 29-ish when he wrote it). There's something very moving about the situation (consider the title, with its now-tragic resonance), and frankly, it makes us more forgiving of material that isn't fully formed or first-rate.

There are some fine things in Boom!, notably two comic songs: "Sunday," a Sondheim parody, and "Therapy," a duet list of his-and-her relationship gripes. But most of the ballads are mediocre, and strung together, much of Boom! sounds like a mawkish mix tape.

It is enjoyably performed, though, by the 11th Hour company. Michael Philip O'Brien (Jonathan) is charmingly earnest, and sings in a hauntingly lovely tenor. Supporting players Lauren Shealy and Steve Pacek are also winning, though both have been encouraged to overact. (In general, there is too much choreography and "business," which overpower some of even the best numbers.) The all-important band and the musical direction are excellent.

By all means, do see Boom! -- a work of touching promise, imaginatively resurrected here. But we do need to keep some perspective: By age 23, Irving Berlin had already written "Alexander's Ragtime Band."

Tick, Tick … Boom!

Through April 29, 11th Hour Theatre Company at Walnut Street Theatre Studio, Ninth and Walnut sts., 267-987-3353, www.11thhourtheatrecompany.org