The very thing that’s made Jason Robert Brown’s 2002 off-Broadway musical work so well on stage since its 2002 off-Broadway debut (followed by many provincial stagings)—its essential theatricality—militates against it on the screen. “The Last 5 Years” originated as a two-person piece, presented on a sparsely furnished set, that covered a half-decade romance-and-marriage told through songs sung alternately by the man and woman. But while his numbers told the story from beginning to end, beginning with their meeting and continuing through the breakup, hers were chronologically reversed, starting from the breakup and working back to their early joy; and they met only in the middle for a duet. The reverse-chronology gambit isn’t entirely new, of course; Sondheim used it in “Merrily We Roll Along.” But Brown further embellished it with the back-and-forth juxtaposition.

On the boards the structural conceit was no problem, but when transferred to film its artificiality becomes oppressive. Adapter Richard LaGravenese has tried to deal with it in a couple of ways. First, he’s “opened up” the play, filming in naturalistic New York locales; but the realistic backgrounds accentuate the synthetic nature of the piece rather than mitigating it. Secondly, fearing that the sung-through nature of the original would be problematic on screen, he’s added scraps of spoken dialogue between them, not always to good effect. A perfect example comes in a scene in which Jamie (Jeremy Jordan), a writer, reads from his enormously successful first novel. The snatch of text he intones before an adoring crowd is dreadful prose, and it would have been better to have left the content of the book to the viewer’s imagination. The other bits of conversation aren’t quite so unfortunate, but they don’t add much either.

By contrast Brown’s songs are often lovely, in an easygoing show-business way that allows him to skip from romantic ballads and heartfelt soliloquies to jazzy numbers and comic patter songs. The quality varies, of course (this listener thought that “The Schmuel Song,” a ditty that Jamie contrives to raise his wife’s sagging spirit at Christmas, is utterly precious, besides going on far too long), and a note of sameness settles in over time, but the music is very well presented. The same chamber ensemble accompanied the singers on stage is employed here as well, though they’re not visible, as they were in the play. And the singing, by Jordan and his partner Anne Kendrick, who’s the aspiring actress Cathy, is superb. Kendrick showed her pipes in “Into the Woods,” of course, and the positive impression she made in that film is more than seconded here.

Both Kendrick and Jordan throw themselves into the thespian side of their performances, too, but it’s here that the musical falters. The essential dramatic thrust arises from the stress put on the relationship by the contrast between Jamie’s enormous success and Cathy’s faltering (or more properly never-taking-off) career. This vaguely “Star is Born” scenario is sound enough, but it requires greater depth of characterization than Brown brings to the couple through his lyrics, which are often earthbound and, when they strive to be emotionally revealing, can come across as overly declamatory. The result is that Jamie and Cathy emerge more as sketches than fully rounded people, and though Kendrick and Johnson do what they can, they can’t fill in all the blank spots.

What we’re left with is the equivalent of a two-singer cabaret act that seems ungainly when transferred to the authentic settings of New York City. And while the sound recording is excellent (and the stars do an excellent job of, presumably, lip-synching to their prerecorded voices, since their singing is far too flawless to have been recorded during filming), the visuals are patchy, looking for the most part as though Steven Miller’s camera was capturing the action on the fly. The washed-out colors don’t help matters, either.

To those—among them LaGravenese, apparently—for whom Brown’s score is reason enough to revisit “The Last 5 Years,” this film version will be a source of great pleasure, since it’s well performed and can easily be called up whenever the mood arises. The uninitiated, however, will find it more of a mixed bag.