`SLIDING DOORS' ROMANCES `WHAT IF' NOTION ABOUT LIFE'S PIVOTAL DECISIONS.

Byline: Glenn Whipp Daily News Film Critic

Spool through the events of your life and undoubtedly you'll come across a few missed opportunities - words not spoken, roads not taken, dates best broken. Everyone has them. Some people love to dwell upon them. If you're one of those people, ``Sliding Doors'' is the movie for you. And even if you're not, the film is still worth seeing as one of the more original romantic comedies to be released in quite some time.

``Sliding Doors'' opens with Helen (Gwyneth Paltrow) leaving her London flat and sleeping boyfriend for her job as an up-and-coming publicist. Her day at the office doesn't last long, though, because when she arrives, Helen is promptly fired for a minor offense. Glum and indignant, she leaves for the subway to go home.

At this point, ``Sliding Doors'' becomes two movies in one. In one scenario, Helen catches the train, arrives home early and discovers her boyfriend, Gerry (John Lynch), having sex with an old American flame (Jeanne Tripplehorn). She moves out, goes to live with a girlfriend and begins a cautious relationship with a new suitor named James (John Hannah).

In the other version, Helen misses the train, gets mugged while hailing a taxi and arrives home just as the girlfriend is driving away. Unaware of Gerry's infidelity, she stays with him, takes a job as a waitress in order to keep supporting his work as a novelist and becomes enveloped in sameness and sadness.

Having dueling movies is a tough concept to pull off, but writer-director Peter Howitt has taken this potentially confusing, distracting premise and fashioned a remarkably engaging movie. The cuts back and forth between Helen's two worlds are handled adeptly and never detract from the story. Often the two Helens find themselves in the same place at the same time - a restaurant, alongside the Thames, a hospital - but in wildly different circumstances, reinforcing Howitt's central conceit of how big a difference one moment can make in a life.

Such a movie could be a portentous affair, but Howitt's detailed, snappy writing and light tone keep things mostly smart and breezy. Paltrow's performance is decidedly understated, particularly for a film which requires dual dramatics. But since there isn't the standard Good Helen, Evil Helen dynamic at work here, Paltrow can dig in and show subtle nuances of Helen's character that are nicely contrasted as the story - or stories - progress.

Hannah (who read the W.H. Auden poem so memorably in ``Four Weddings and a Funeral'') demonstrates that he can be just as charming and funny as Hugh Grant and perhaps even more so. He and Paltrow make such an appealing couple that it's sometimes disappointing when the movie leaves their love story.

But the film never strays for too long. Original, shrewd and funny, ``Sliding Doors'' is the kind of romantic comedy that everyone talks about wanting to make but never quite succeeds. Howitt, in an auspicious writing and directing debut, will never have to wonder about a missed opportunity.

THE FACTS

The film: ``Sliding Doors'' (PG-13; language and some sexuality).

The stars: Gwyneth Paltrow, John Hannah, John Lynch and Jeanne Tripplehorn.

Behind the scenes: Written and directed by Peter Howitt. Released by Miramax Films and Paramount Pictures.

Running time: One hour, 45 minutes.

Playing: Citywide.

Our rating: Three and One Half Stars.

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Photo

Photo: ``Sliding Doors,'' co-starring Gwyneth Paltrow and John Hannah, examines how singular events in our lives can change everything.