ON TUESDAY NIGHT, most of Massachusetts thought about the unexpected primary dump of Governor Dukakis, but the opening night crowd at the Colonial Theater was oddly removed from all the shenanigans outside. They were there for a Good Time, and they were determined to get it for the price they had paid. Well, when the brand new musical version of King of Hearts finally ended, the crowd stood up and cheered. You don't usually see that on opening night for anything. There are two possible explanations. First, and most obvious, is that Boston is a pitifully poor town for professional theater; even the faintest whiff of the real thing overjoyed the patrons. Second, and less plausible, lurks the notion that King of Hearts is a great musical. The answer lies between the two.

The musical, America's biggest contribution to the stage in this century, relies on a set of givens that has never really changed. Give 'em a couple of big production numbers, a whole lot of dancing, some love and a few funny lines, and they'll go home happy. Unless the book waxes trite beyond belief or the singers are tone-deaf, what you usually need in a musical is a lot of money and the kind of house-filling draw no producer can resist.

With all that in mind, King of Hearts can be observed in proper perspective. As a piece of theater, it is not awfully good. As a musical, it fluctuates wildly between ordinary and very good. And as a money-maker, it will do quite well, both here and in New York, where the theatrical season has been so bad that anything short of the Flying Zambinis will sell.

Director Ron Field, scriptwriter Joe Stein and song team Peter Link and Jacob Brackman '65 were faced with a difficult problem in adapting Philippe de Broca's wonderful film about World War One in a town suddenly overrun by loonies. It's a tough act to follow, and on the whole the film still comes out ahead. But the musical version remains enjoyable; certainly it is diverting.

The story follows the whimsical adventures of an American soldier (changed from British in the film) sent into a deserted French village to find explosives left by retreating Germans. What he finds is not bombs, but wackos. Lots of wackos, residents of the local loony bin who find themselves out on the streets after the regulars flee. You can just imagine what ensues.

Like most musicals, King of Hearts depends heavily on gimmickry and convention to cover a fairly mediocre book. The dialogue sometimes becomes frighteningly simplistic, even fatuous, and most of the "jokes" aren't too funny. But the songs, which range from standard to excellent--particularly "A Stain on the Name" and "Nothing, Only Love"--and the many dance numbers make the show. Field's choreography, although not original, is effective, helped along by several excellent dancers.

Donald Scardino, who unfortunately reminded me too much of Ronnie Howard, plays Johnny, the American soldier, with just the right touch of geewhiz and charm. He is an innocent cast among the crazy, and he reacts accordingly. His voice isn't great, but he pulls off his numbers with no major trouble. Millicent Martin, as the madam, has too many songs and becomes boring after the first act. The show runs about two and a half hours--far too long, particularly in the first act--and I suspect some of Ms. Martin's numbers will feel the knife in the near future.

THE REST of the cast--loonies, soldiers, and even a walk-on pig--perform quite adequately, with occasional flashes of brilliance. Still the technical aspects of the production provide the real thrills of the evening. Santo Loquasto's unit set looks great and functions nicely, the costumes are imaginative and attractive, and the notion of putting both American and German trenches in the orchestra pit clicks, even if the scenes involving the doomed soldiers are mostly awkward and extraneous. There is one nice a capella number for the soldier boys, and an almost-touching dream sequence in which a temporary truce allows the opposite sides to get to know each other. All in all, King of Hearts comes off as an extremely slick production, calculatingly geared for success.

There remains a sense of futility in searching for thematic depth in usually vapid musicals, but in this case the apparent wishy-washiness of the implicit message, if there is any, becomes rather annoying--but not until well after you leave the theater. De Broca's film contained both a muted anti-war message and an eloquent statement contrasting the so-called crazies in the asylum with the real crazies in uniform, who kill each other in a quest for peace. Who's really crazy, and all that. Neither of these implicit themes comes through clearly in the musical version. Both of these themes are discernable, of course, but they are undermined by all the dancing, singing, and general frolic on stage. When Alan Bates shed his clothes and stood at the asylum gates at the close of the film, it was clear that he was rejecting the crazy world outside for the sane world of the crazies. When Johnny runs into the bin at the end of the musical, well, it's just as easy, given the build-up, to assume that he's going in there because his buddies are there, the people who've been nicer to him than anybody else. War? What war? This is a musical, baby, and the soldiers might just as well dance off into the sunset. Something essential gets lost, but somehow it doesn't matter. Unless, as with most musicals, you muse at length.

King of Hearts has a lot of shtick, boundless energy, and in all probability a bright future. It's the kind of show many reviewers will hate, because of its flaws, but audiences will love it, because it's fun. And that's what musicals are all about. Give 'em the old razzle-dazzle and you'll leave 'em in the aisles, screaming for more, no matter what's going on outside the theater, back there in reality.