It's hard to criticize a piece of musical theater that is as ambitious, poignant, and unique as Stuck Elevator without coming off as a philistine, and for that A.C.T. deserves some credit. The world premiere musical — it's really more of an operetta, but we'll get to that in a second — with music by Byron Au Yong and a libretto by Aaron Jafferis has some lyrical and soaring moments, but ultimately the ambition of the music itself may have gotten in the way of the staging, and the story.

The subject matter of the piece makes for an intriguing stepping off point for a modern tragic opera: An illegal immigrant gets stuck in a Bronx elevator after delivering some Chinese food, and rather than call for help, he waits quietly for four days out of fear of being found by police and deported. It carries with it the weight of the immigration debate, the narrative power of a lone figure lamenting his fate, and images of the mythical American dream. It's these nuggets of pathos and drama that Yong and Jafferis, along with director Chay Yew, use to build a series of sung vignettes, recitatives, and songs that tell the story not only of our central character's current predicament, but also of his wife and child back in China, the nephew he lost in the crossing, and the people he works with at the Chinese restaurant.

As Guang, the delivery man stuck in the elevator, Julius Ahn is a commanding and impressive presence. Playing a pathetic character in a more pathetic circumstance, he sings with power and plays his character with admirable subtlety. Also admirable is how he never leaves the stage in the course of the play's 81 minutes.

The rest of the ensemble, totaling five with Ahn, are also very talented, and by the close of the play, with the stunning harmonies of the final song ("Rise"), it's impossible not to walk away with a sense of awe and relief. Marie-France Arcilla is terrific as the lone female voice among them, playing Guang's wife Ming and other characters, and Joel Perez deserves praise as well for his role as Guang's coworker Marco, and for adding layers of rap and rhythm to the piece.

Daniel Ostling's dynamic urban set, with the mobile elevator itself and well used projections at the rear, is a beautiful thing, and works extremely well throughout.

One can't help but notice flaws in the overall work, though. Despite efforts to fictionalize and flesh out the narrative from the actual story from which it was inspired, we can't help but wish there was more to it. The character of Marco adds some In the Heights-style flair via contemporary Broadway, but the majority of the score points more to opera, and has a stiffening affect that undercuts that modernity. It actually feels more like a piece of music than it does a piece of theater, and if we were reviewing it as such, we'd probably call it a success.

But as a piece of theater, it's weighed down by those flaws, dramatic tedium (one entire sequence, for obvious reasons, is just about urination), and several slow or superfluous scenes that serve to make its quick running time feel longer than it should. The audience begins to fidget by the final third, and numbers like the whimsical (but not that amusing) "Takeout Man" with its faux wrestling setup, and the false escape that occurs just ten minutes or so prior to Guang's actual escape (and the play's end), feel like they should have been cut. A false, or fantasy, ending just seems cruel when you're actually itching for something to end.

Because how can you not want a play about a man stuck in an elevator to hurry up and end? That, perhaps, is the ultimate problem with the piece. As interesting and timely as it is, Stuck Elevator remains forcibly limited in its scope, and the audience can't help but feel claustrophobic — which is never a great feeling when sitting down for a night of theater.

Stuck Elevator plays through April 28. Get tickets here.