'Zelig' stretches the language of film; Woody Allen's bold, ingenious way with a comic tale

I once asked Woody Allen why his popular ''Annie Hall'' had such a broad range of moods, from bright farce to sad romance, and used so many cinematic tricks to tell its story.

The reply gave me a strong clue to Allen's thinking about film. Years ago, he said, people saw the world in largely physical terms, and movies reflected that view. They showed heroes taming nature, pioneers building a civilization, Charlie Chaplin striking it rich in the Klondike.

But now, he went on, our world seems more internalized, less concrete. And there's the rub for moviemakers. How do you show a computer finding an answer? How do you portray a culture that's hooked not only on video games and microcircuits, but on foggy concepts like ''human potential'' and psychiatry?

Allen's solution has been to stretch the language of film. Convinced that movies are mirrors of the way we see things, he'll reach for any style or device - from sober storytelling to camera trickery - to capture not just stories and characters, but the mental and emotional states that make them tick. Hence the grab-bag imagery of ''Annie Hall,'' the melancholy elegance of ''Manhattan,'' the airless rumination of ''Interiors,'' the grating visions of ''Stardust Memories.''

Where does the new Allen comedy, Zelig, fit in? Visually, it's the boldest and most experimental picture he's made so far. Wrapped in a haze of American history and myth, the story is told entirely in the grainy images of old newsreels and home movies, punctuated with deliberate scratches, splices, and missing frames.

Why this brave, risky approach to a very comical tale? I think it's because Allen takes that comical tale very seriously. ''Zelig'' isn't only about its main character, a fantastical ''chameleon man'' who can change his looks and personality at will. It's an ingenious movie metaphor for a whole society that's anxiously evolving, and misses the sense of identity and purpose it used to have. The fake ''documentary'' format takes it beyond its hero, making him the bittersweet symbol of an uncertain culture in an uncertain century.

Allen himself plays Leonard Zelig, a nobody. Longing for acceptance, he learns to adapt his mind and body to match any company he's in, and - like many a science-fiction character - loses control of his special gift. The movie recounts his chaotic life as if he were a once-renowned but now-forgotten celebrity. Much of the going is hilarious, like the best Allen comedy. And there are several touching scenes, especially when Mia Farrow is on screen as the doctor who wants to cure Zelig but learns to love him.

Zelig's story, and its setting in the 1920s and '30s, give Allen plenty of real and fictitious targets, from flagpole sitters to politicians. But I think the key to the film comes in an early scene, when Zelig is asked why he developed his bizarre ''chameleon'' talent.

We see his image in a still photo and hear his reply as it might have been recorded with vintage equipment decades ago. ''I wanted to be liked,'' he says, and we can barely hear his voice, so old and scratchy and noisy is the recording. He repeats himself - ''I wanted to be liked'' - and it's as if Allen (the chameleon filmmaker) were speaking from his heart, not daring to face us directly, but filtering his poignant words through a mask of cinematic history that's as elaborate, entertaining, and revealing as anything his career has yet given us.

Am I being too solemn about the uproarious ''Zelig,'' easily the funniest movie of the past several years? Yes. But the sublime and the ridiculous often run neck and neck in Allen's films, and the gentle sadness of ''Zelig'' has lingered in my mind just as strongly as the explosive jokes and sight gags. It's also a stunning picture to look at, with astoundingly precise re-creations of bygone artifacts, and clever mixtures of new and old footage.

For years I've been rooting for the movie industry to loosen up and try something really fresh for a change. The few attempts that have been made - such as ''Pennies From Heaven'' and ''Dead Men Don't Wear Plaid'' - have fallen on their faces. ''Zelig'' is a radical experiment that pays off on all levels. It's a triumph from the most audacious and intelligent funnyman we've had since the heyday of Chaplin and Keaton. Marathon film

At about 15 hours long - and some of those hours brilliant - Berlin Alexanderplatz is the magnum opus of the late West German filmmaker Rainer Werner Fassbinder.

But it presents the exhibitor with some unusual challenges. How do you present a picture this long without (a) fracturing its continuity or (b) driving the audience crazy?

TeleCulture, the American distributor of ''Berlin Alexanderplatz,'' has tried several methods as the film has traveled to theaters, museums, and universities around the United States.

In some places, the whole film has been shown in two daylong installments, then repeated in smaller doses over a week. In other places the epic has been broken up into three-hour segments - easy to take, but requiring several return visits. When several screens have been available at once, in a ''multiplex'' theater, different episodes have been screened at the same time, allowing each person to set up an individual viewing schedule.

For the film's coming New York engagement, beginning Aug. 8, the conservative method is being used: five installments of three hours each, screened for one week apiece. That's reasonably easy on the eyes and ears, though I enjoyed the intensity of seeing it all in two sessions. In any case, there's nothing wrong with the splintered approach, as the picture was originally made for TV serialization.

Another engagement coming soon is in Los Angeles, where an Aug. 7 marathon will present the whole movie in one swoop, to be followed by three-hour installments each Tuesday and Wednesday at two theaters. The film is also slated for a San Francisco run in October - exact dates aren't set yet - and it will continue to travel around the US indefinitely.

Even aside from its length, ''Berlin Alexanderplatz'' isn't for all viewers, with its sometimes harsh portrait of a small-time hood who decides to go straight and barely survives the events that follow. But the movie's technical wizardry and striking performances make it a far better testament to Fassbinder's career than his last work, ''Querelle,'' a tale of murder and lust that achieves some striking visual effects but misses the grim poetry of the weird Jean Genet novel it's based on.