When "Heaven's Gate" opened in New York last November, it was 3 hours 40 minutes long. Critics excouriated the movie, and the next day writer-director Michael Cimino drafted a statement asking United Artists "to withdraw the film from distribution temporarily to allow me to present to the public a film finished with the same care and thoughtfulness with which we began it . . ." UA canceled the scheduled theatercial openings after going ahead with a second, successful preview in Toronto and allowing a one-week engagement in New York, evidently to justify a 1980 tax write-off on part of the endangered $36-million investment, three times the budget initially authorized.

In the wake of the catastrophe, UA president and chief executive officer Andy Albeck was replaced. Advertising vice president Hy Smith left the company last week. And during the winter of UA's dicontent, Cimion's name became the Hollywood equivalent of Lockheed or Chrysler.

But five months after the initial disaster, the 2 1/2-hour recut version of "Heaven's Gate" opened yesterday at 850 theaters around the country, with a new $6-million ad campaign and a new optimism on the part of studio executives.

The original advertising pictured Kris Kristofferson slouched in a doorway with a gun in his hand. The new ads show Kirstofferson and costar Isabelle Huppert embracing against the background of an American flag. The switch, says a UA spokesman, shows how the "focus has changed from an action film to a love story." Director Cimino (who still has two films to go in a three-picture deal with UA) and three editors worked together those five months, reducing the emphasis on the conflict between Wyoming immigrants and wealthy stockmen and accentuating the love story.

The studio now believes that the picture can turn a profit: The initial bad publicity "will work in our favor to provoke curiosity," a UA executive says, and Cimino's sizable following in Gate" will do better abroad than at home. UA made about $30 million in profit from distributing Cimino's last film, "The Deer Hunter," in Europe, and hopes that worldwide interest in "Heaven's Gate" can turn it into a 1981 version of "apocalypse Now," another long, over-budget blockbuster which went on to earn some $200 million in worldwide rentals.

None of the film's stars attended the Thursday night reopening in Hollywood (most are on location with other films). The audience applauded at intervals, while outside picketers protested alleged violence to animals in the cock-fight and gun-fighting sequences. Cimmino attended, but avoided the public: According to a studio spokesman, "He just doesn't feel like he has anything to say."