**_By-the-numbers third instalment lacks the imagination of the previous one_** Five teen girls hold a slumber party when the parents of one of them are out of town. As several guys crash the party someone with a huge drill and murderous intent also invades the proceedings. "Slumber Party Massacre III" (1990) starts out promising, but becomes routine by the midpoint and never recovers, which isn’t helped by increasing tastelessness. While it’s arguably on par with the first film from 1981 (which I slightly prefer), it lacks the impressive creativity of 1987’s part II, which had pizzazz. A...