Manhattan Murder Mystery.

Woody Allen's latest, Manhattan Murder Mystery, was made under crisis conditions; intended for Mia Farrow, it was hastily readjusted for Diane Keaton. One could make excuses, but an artist such as Allen fancies himself to be doesn't accept special pleading. Life is always difficult; making a movie is not a burden, but a respite.

If ever a picture seemed improvised, slapped together, disrespectful of the demands of the medium, this is it. Written by Allen with his off-and-on collaborator Marshall Brickman, it concerns a nice, civilized Manhattan couple who become involved with their immediate neighbors, the Houses. When Mrs. House dies the very next day, Carol Lipton (Diane Keaton) considers the circumstances suspicious, and decides to play Nancy Drew. Her husband, Larry (Allen), disagrees, and urges her to mind her business. Soon she is coming upon disturbing details, and eventually even the skeptical Larry joins in the sleuthing.

What a mystery - particularly a low-key, this-could-happen-to-anyone kind - needs is verisimilitude. Since neither the commission of the crime nor its unraveling involves masterstrokes of cerebration, it behooves the script to draw us in through sheer believability. But Allen and Brickman are trying for something else as well: comedy. So we get that occasionally effective hybrid, the comedy-mystery. In that case, however, the comedy had better be funny. What happens if the thriller aspect doesn't thrill very much, and the comedy doesn't get many laughs? This.

To start with the verisimilitude. Coming home one evening to their apartment house, the Liptons are enticed to the House apartment down the hall. The couples have just met, and Mr. House, who is a bit of a bore, is dying to show off his fabulous stamp collection; though pleased to make new friends, Larry is fuming because this is making him miss the Bob Hope movie on television that he was dying to watch. I ask you now, is there any with-it New York couple such as the Liptons without a VCR? Well, maybe they just forget to set it. No problem: Larry can excuse himself for one minute, set the machine, and come back. Even the most rabid philatelist would brook such a piddling interruption.

Again, Carol gets hold of the House apartment keys in a way that even for New York's shoddily run buildings strains all credulity. Snooping around the House apartment, she is surprised by the widower's unexpected return; hiding under a bed, she escapes detection. But she loses her glasses there, and House finds them, later, under his bed. Now, a person needing her glasses to see is not going to lose them, of all places, under a potential murderer's bed. If her needy eyesight doesn't clue her in, surely her instinct of self-preservation will. But as if this weren't preposterous enough, House swallows Carol's pathetic explanation, and overlooks even her and Larry's frantic behavior while they're cooking up their indigestible lies.

And so it goes, from absurdity to absurdity. One more sample: sitting in an alcove at a wine tasting, Carol glances out a window and sees on a rapidly passing bus the supposedly dead Mrs. House. Even assuming that one's perception is not blunted by the critical tippling, can one spot a person one has met only once before as she rides a passing bus? To say nothing of coincidence, which in this film is stretched to dimensions that would have given Thomas Hardy pause. The slovenliness and cynicism in scene after scene knows no limits or shame. There is even an all-night garbage-disposal plant somewhere in New York, ablaze like Vulcan's workshop, where anyone can come and dump cadavers undetected, for there is no human being of any kind around.

Okay, so this is more of a comedy. What kind of comedy? Mostly marital spats of the Liptons, as she snoops and he grouses. This yields those querulous, high-pitched, whiny Allen natterings that I find funny only in the small doses in which they don't come. In a New York Times Sunday piece, Maureen Dowd quotes two raisins from this soggy cake right in her second paragraph. In one, Larry tells Carol that she is acting crazy, and that she should save something for menopause. In the other, he avers there is nothing wrong with her that "a little Prozac and a polo mallet wouldn't cure." Since Miss Dowd has divulged them, I feel free to repeat them, but there go half the funny lines the film has to offer.

Visual excitement has never been Allen's strong suit, and it isn't here either. The final confused shootout occurs backstage in a movie theater showing the closing scene of Welles's The Lady from Shanghai, which is a shootout in a mirrored funhouse. Now, if there were some sort of twist here, if this weren't just a disoriented reckoning within another disoriented reckoning, it might be fun. A drunken orgy against a drunken-orgy background is nothing; a Boy Scout jamboree so framed is something.

Only Allen and Miss Keaton get much of a chance to act. Alan Alda is brought in as a possible extracurricular love interest for Carol; Anjelica Huston, ditto, for Larry. But both these plot elements are promptly swept into a comer and forgotten. Similarly, a college-age son is dragged in for one brief scene, only to vanish forthwith. Miss Keaton would be all right for her part if she were willing to settle for clothes and a hairstyle befitting her weight and age. As for Allen, although he is quite amusing getting hysterical in a stalled elevator, the rest of the time he is hard to watch, especially as a love object for two women. He has the face of a middle-aged imp, a too-rumpled Rumpelstiltskin - a nerdy, over-age gnome impossible to warm to. There is amusing ugliness: think of Groucho Mark, of Buster Keaton. And there is the other kind: this.