`BACK TO THE FUTURE'' came out in 1985, and when the box-office receipts were added up it turned out that Universal Pictures had earned more than $100 million with its science-fiction comedy - a fact as fantastic as anything in the movie. With that kind of money at stake, it was inevitable that a sequel would come racing down the space-time continuum. And sure enough, ``Back to the Future Part II'' has arrived. Once again the filmmakers are director Robert Zemeckis (who also made ``Who Framed Roger Rabbit'') and screenwriter Bob Gale, his frequent collaborator. Another key player this time is the Vistaglide camera, a computerized device that helps a performer do two roles in the same scene, which happens quite a lot in this picture. It facilitates some impressive special effects, as it did in ``Roger Rabbit,'' but it's also reaping the blame for a lackluster photographic style that makes the movie less than eye-boggling. (Dean Cundey did the cinematography, with help from Jack Priestley.)
Unless you've been back in the future for the past few years, you already know the main characters of the yarn. Marty McFly is a nice young man who dreams of being a rock star but lives an ordinary life. Not so ordinary is his friend, Emmett Brown, the maddest mad scientist in the world. He's invented a time machine - made from a DeLorean automobile - and in the first movie, he and Marty had some deliciously goofy adventures together, especially when they visited 1955 and played matchmaker for Marty's own mother and father.
The new picture starts exactly where the first one left off, with Marty and Doc Brown zooming to the year 2015 to save Marty's future children from a catastrophe. They take care of the crisis easily, but during his trip to the future Marty gets an idea: If he picked up a 2015 sports almanac and brought it back to 1985, he could win all kinds of wagers on sporting events, just by looking up the final scores. Doc talks him out of this mercenary idea, but it's overheard by the movie's nastiest character, Biff, who takes a time-trip of his own to put such an almanac in the hands of his own, earlier self. The young Biff gets rich and famous by winning every bet he makes, becomes even more insufferable than he was in the first movie, and causes some awful changes in the world around him. Marty and Doc have a big job to do: altering the future and the past, so the present will turn out all right.
If this sounds confusing - it is, a little. Fans of the original ``Back to the Future'' may enjoy figuring it all out, and it's amusing to see scenes from the first movie reappear in the sequel, but with new meanings. I also liked the portrait of what 2015 might be like; among other predictable things, ``Jaws 19'' is playing at the local movie theater. The ever-likable Michael J. Fox is good as Marty (and briefly hilarious as Marty's future daughter), and Doc Brown is still the best movie part Christopher Lloyd has ever played.
Unlike the first ``Back to the Future,'' though, the sequel doesn't stay fresh and surprising all the way through. After a few good scenes, the plot gets too tricky, and the filmmakers keep walloping us with one chase scene after another. On top of this, we have to wait for another sequel (which has already been partly filmed) to see how the story comes out. It's going to be a western, and I'm sure it'll pack some surprises. But for the moment, I'm tired of the future, and I suspect other moviegoers will be, too.