FROM WHAT WE can gather today, life in the Dark Ages was no picnic. You had your disease, your ignorance, your intermittent famine. There was little interracial sensitivity. Trees seemed to have lacked leaves altogether, and you could never get the muck off your shoes, even indoors. Kings were greedy and whined a lot. At the first sign of trouble, they threw up their hands and sacrificed a virgin or two. The peasants, weakened by long hours of hunting for roots and small rodents, mustered little culture of their own, preferring to spend their weekends puttering around the hovel and swearing. Everyone was embarassingly short.

In addition to wagon congestion on market day, there was one other overriding problem, and that was dragons. Predictably merciless when they terrorized a village--as was their occasional wont--dragons became much more unpleasant when pestered by heroes with long spears. One such confrontation is depicted in Matthew Robbins' Dragonslayer, the story of a kid who wears burlap clothing but makes good anyway.

As the movie gets underway, we realize that we have actually missed most of man's grimmest hour. Christianity has penetrated deep into the British backwoods, while the monster population has taken a perilous tailspin. Only one winged geezer remains, living quietly for the most part with a litter of dragon cubs. Understandably, even one fire-breathing creature has the locals a little unnerved, especially since once a month, their ruler picks a young maiden to be fed to the beast. Thus the search for a savior begins, setting up the required battle of good versus evil.

Dragonslayer, though technically impressive, is not a very ambitious movie. Robbins sticks close to the traditional outline of heroic deeds interwoven with improbably convenient love. Ulrich, an over-the-hill sorcerer who still wonders why he could never turn lead into gold, sends his young apprentice, Galen, to conquer the dragon. Galen befriends a pretty young woman who wears men's clothing. Once she gets her wardrobe sorted out, he faces his enemy, fortified by his own bravery and a bit of old-fashioned hocus-pocus.

The film lurches from one battle scene to the next with little substance in between. Most of the problem can be attributed to Peter MacNicol's peanut butter-on-milquetoast portrayal of the would-be hero. Tireless in an irritating way, MacNicol inspires little interest in his quest; he never seems the least bit ambivalent about clambering down into murky caves and facing off against the 50-foot lizard who has just torched the whole kingdom with a few sneezes. As a lover, he is tepid at best, remaining oblivious even when his ladyfriend mentions at one point that she's still a virgin, and the dragon only eats virgins, and isn't there something they could do about that?

THANKFULLY--WE DON'T have to wait very long between fire-breathing sequences; Robbins knows what the kids have come to see. With theater-rattling thumps, our dragon stalks his turf, and like a B-52 with scales, swoops over hapless victims, booming displeasure with the human race. Great care has been taken to construct a plausible lair for the villain, a spooky underground grotto containing an Olympic-sized pool complete with burning water and oozing ceiling. The little baby dragons, who display a revolting appetite for freshly killed princess and give Galen some initial resistance, may provoke more than a few people to go home and flush their salamanders and iguanas down the toilet while there's still time.

Of all the characters in Dragonslayer, the beast displays the most depth. A last, lonely survivor, it is dying a slow and painful death without all of this trouble from outsiders. When it comes upon its massacred offspring and nudges their mutilated little bodies in desperate hopes of finding a trace of life, you will no doubt feel more sympathy than when some damsel gets herself burned to a crisp. If only there had been some way of keeping the dragon in front of the camera more, perhaps they could have rewritten the whole story and done it from the bad guy's point of view

As a package, the film will leave you dissatisfied with its triteness and perhaps a bit ticked off that Robbins thought he could retread a tired script merely by adding fancy special effects. The missed opportunities seem obvious when, for example, he bungles the easy juxtaposition of monotheism and black magic in a flurry of cliches and char-broiled priests. Risking very little, Robbins lets his movie get bogged down in Middle Ages muck, where it is continually trampled by hordes of frantic peasants and finally burled under the rotting carcass of old fire-breath himself.