Towering performance by Matt Damon in the lead, and a superlative ensemble headed by a terrific Robin Williams, elevate "Good Will Hunting," Gus Van Sant's emotionally involving psychological drama, a notch or two above the mainstream therapeutic sensibility of its story. Centering on a brilliant working-class youngster who's forced to come to terms with his creative genius and true feelings. Miramax could score big with extremely enjoyable pic whose old-fashioned virtues should play well in big cities as well as in Middle American shopping malls.