Steven Spielberg's marvelous science-fiction adventure fantasy, "Close Encounters of the Third Kind," first released at Christmas of 1977, has returned in a slightly altered version called "The Special Edition." The official explanation for this revision is that Spielberg wanted to enhance the finale with the depiction of what the protagonist saw upon walking aboard the majestic mothership of the visiting extraterrestrials.

Studio publicity quotes Spielberg as saying, "You can often have different ideas or feelings about a film months or years later, and there are points that can be added to improve the story's impact . . . The new footage takes Richard Dreyfuss one step further, but the mystery still exists . . . I'm glad I was able to enhance the work to meet my original vision . . ."

The ads lead one to believe that the visual delights of the original "Close Encounters," which ended with a brilliantly sustained and profoundly stirring pictorial spectacle -- arguably the greatest single spectacle in contemporary filmmaking -- will be significantly enlarged.

While not way out of line, the claim is certainly exaggerated. The new scene is interesting and attractive as far as it goes, but not a major addition to the original. In fact, the sequence is rather awkwardly inserted. Dreyfuss reappears crossing the threshold of the ship's portal. He stops -- that was "one" step further, remember -- and gazes upward at perhaps two or three minutes of special-effects footage illustrating the ship's decor.

Inside a towering central chamber we see banks of lights being recessed automatically into the walls, smaller spacecraft returning to a lofty docking bay that vaguely suggests a beehive (easily the most effective of the new effects), figures moving behind long rectangular windows at high elevations and a shower of sparkles. That's it. There is no interplay with either aliens or the team of astronauts that Dreyfuss' character, a Muncie, Ind., linesman named Roy Neary, was permitted to join.

The sight of Dreyfuss standing by himself recalls a nagging omission that remains uncorrected: Spielberg's failure to append a shot depicting the other passengers boarding the mothership. Now Dreyfuss really seems to be a solitary passenger, an impression that threatens the credibility of the sequence. Obviously, Spielberg couldn't get the whole gang back together, although that's what the situation calls for.

I had formed the impression that the new sequence inside the mothership would be extensive, obliging Spielberg to cut back on some of the expository footage. Instead, he arrives at about the same running time as before by ditching a few scenes in order to make room for restored scenes. On the whole, the exposition has been improved by the new deletions, restorations and inserts, but a long version incorporating every scene from the 1977 and 1980 prints would serve fans and movie history best of all.

Some scenes are now compressed -- for example, the dinner-table scene in which Neary begins making a mountain out of his mashed potatoes. Others are expanded, notably the sequence introducing the Neary family.Gone entirely are the scenes of Neary reporting for emergency duty at the power company; the Air Force press conference; Neary bustling about the yard gathering raw material for his sculpture of Devil's Tower, and Neary attempting to sneak through the military cordon sealing off Devil's Tower.

Carl Weathers, who played the soldier, becomes a casualty of the "special edition." Roberts Blossom, cast as the farmer who eagerly awaits the UFOs barely survives.

Spielberg has added a new strange occurrence, climaxed by an astonishing sight gag, discovered by the scientific team researching the clues leading to the decisive encounter. But the most impressive addition is a restored sequence of marital conflict between Dreyfuss and Teri Garr. It begins when Mrs. Neary awakens at night and hears her husband whimpering in the bathroom. She picks the lock and discovers him sitting fully clothed in the tub with the shower going full blast. Her initial impulse to comfort him soon gives way to further exasperation at this new evidence of his erratic behavior, and their argument rouses the kids.

It's a scintillating passage of domestic turmoil and recrimination, culminating in an image that seems almost too haunting: Neary's eldest son glaring at his father in shame and anger, evidently convinced that dad has totally flipped. Since the family is never reconciled after Neary decamps for Devil's Tower, this sequence leaves harrowing reverberations. It's one of the strongest dramatic interludes Spielberg has ever directed, so one is grateful to see it salvaged. Moveover, it reinforces an impression left by the earlier domestic scenes: Teri Garr is the film's best performer.