The theme of alternate realities is a popular one in sci-fi generally, and, it seems, specifically among modestly-budgeted films in the field. Not long ago Mike Cahill gave us “Another Earth,” about a mirror planet to our own, and now we have James Ward Byrkit’s “Coherence,” a micro-budget affair that reduces the phenomenon to the neighborhood level. The result is a “Twilight Zone” dinner party whose guests frankly wear out their welcome.

The action—or, to be precise, mostly talk—takes place at the suburban house shared by actor Mike (Nicholas Brendan) and his wife Lee (Lorene Scafaria). They’re the ones hosting three couples: Kevin (Maury Sterling) and his girlfriend Em (Emily Foxler); Hugh (Hugo Armstrong) and his wife Beth (Elizabeth Gracen); and Amir (Alex Manugian, who collaborated with Byrkit on the story) and his date Laurie (Lauren Maher). Things are a bit tense from the start, since Laurie happens to be one of Kevin’s exes, which annoys Em. But generally things settle into an easygoing hubbub, with conversation banal enough to have been created—as the makers note—through improvisation among the cast.

There are, however, parts of the dialogue that hint at what’s to come. Mike talks about his role on a TV series called “Roswell,” for example, and Em offers a long anecdote about how her great chance at success on the stage was derailed when she quit a job as an understudy after a more famous actress stepped into the lead she was supposed to have played, only to have the new understudy become a star when she took over the part. Another topic of discussion involves a comet that’s passing close by to earth that very night and that appears to disrupt phone and electrical service when it arrives.

That takes the eight acquaintances into talk of theories derived from quantum physics about alternate universes and parallel lives, which seem to be confirmed when a walk down the road reveals that the occupants of a nearby house appear to be mirror images of themselves. And it seems that other houses share that unnerving reality. Even more unsettling, there appears to be some sort of displacement zone through which the occupants of one house can travel to another without even realizing it. They catch on to this fact, however, and devise remedies designed to insure that they’re in the “right” place.

All of this is an amusing enough conceit, however feeble its theoretical foundations, and for the most part the script plays fair with the twists it brings—like the accusation that the hostess has brought it all about by drugging the food and drink. But there are some serious flaws in working out the various permutations that arise. One involves the shaky-cam cinematography of Nic Sadler and Arlene Muller, which may be intended to lend a sense of authenticity but comes across looking merely messy. Another is Lane Pereira’s editing, which uses sudden blackouts as a visual motif that gives the picture a start-and-stop rhythm that grows increasingly tiring.

But the biggest obstacle to enjoyment of “Coherence,” even as a sort of impersonal puzzle, is that the characters are such an irritating bunch that the idea that there are multiples of them is more frightening than anything that happens to any of them. And the fact that they were developed through the actors’ improvisation is no help; it only leads you to suspect that the actors themselves aren’t all that likable. On the positive side, Kristen Ohm Dyrud’s score gives the movie an otherworldly feel.

For most of its running-time “Coherence” is a fairly cerebral affair, but in the end it deconstructs with an act of violence that’s pretty ugly. Yes, it’s supposed to emphasize how far people might go to protect their individuality—a perverted expression of self-defense. But what the denouement seems to represent is a failure of nerve of Byrkit’s part, a lack of faith not so much in humanity as in his own ability to come up with a more intelligent close. On the other hand, it might serve to improve what could well be the basic motive behind the film—to serve as a professional calling-card for bigger, more remunerative projects.