Amiable, entertaining sequel has the ghostbusting boys reteaming five years after their last adventure to save N. Y. C. from a slime attack of gargantuan proportions, generated by all the ``negative energy'' in the air of the Big Apple. Longish but good-natured, with some solid laughs along the way. Chloe Webb has a funny unbilled cameo as a guest on Murray's cable TV show.