“Impuratus” (* out of four) was an insufferable horror slog about a police detective (Tom Sizemore) who investigates a patient in a hospital (Lew Temple) who has obvious supernatural ties that threaten all of their safety. Grueling and pretentious and actually rips off some of the plot of “The Exorcist III” (my personal choice for the worst film of all time). Yet another waste of Sizemore’s talent. Mark David’s stark and foreboding cinematography is film’s sole worthwhile component.