Robin Williams' stand-up persona may represent the runaway id personified, but in the '90s, his movie persona has devolved into a twinkly eyed, perpetually childlike symbol of sentimentality at its cheap, vulgar worst. Williams' latest heartwarming epic is Bicentennial Man, a typically calculated vehicle adapted from an Isaac Asimov story. Williams plays a servant robot who, under the tutelage of kindly patriarch Sam Neill, develops emotions and gradually takes steps to become human over the course of 200 years. In the process, he falls deeply in love with Neill's great-granddaughter (the quasi-incestuous implications of their union strenuously avoided at all turns) and becomes a fabulously wealthy inventor. It's a fairly intriguing premise that would seem to lend itself to dark humor, pointed allegory, and social commentary. Under the direction of Chris Columbus (Home Alone, Mrs. Doubtfire), however, it mostly serves as a delivery system for nearly lethal doses of sentimentality. After all, if one lifetime can supply untold amounts of sloppy sentiment, just imagine the potential for several lifetimes' worth of teary deaths, tasteful weddings, and bittersweet partings. Films have offered many fantastic visions of the future, but the world depicted in Bicentennial Man is so whitewashed that it seems inspired more by Martha Stewart than Kubrick or Lucas. Running 136 minutes, with James Horner's sappy score constantly keeping things in Hallmark-card territory (not that the film needs much help), Bicentennial Man is awfully synthetic for a film glorifying the messy imperfection of humanity.