The extremely uneven third entry in Gore Verbinski’s popular franchise based on the famous Disney amusement park ride begins slow and ascends gradually toward levels of mild entertainment: it’s densely plotted, convoluted, confusing at times, mildly uninteresting at others, and way way way overlong. Let’s see if I’ve got this right: the plot involves rescuing Captain Jack Sparrow (Johnny Depp) from a hallucination-inducing Purgatory; an Asian pirate captain (Chow Yun-Fat) who meets an untimely demise; the ongoing romance between Ms. Swan (Keira Knightly) and William Turner (Orlando Bloom); an attempted truce with the on-again/off-again villain Barbossa (Geoffrey Rush); a sea witch/goddess called Calypso; and the Pirate Council’s war against the British Royal Navy armada. Yes, with a sometimes painful, sometimes enjoyable running time of 168 minutes, this film has enough plotlines for an entire season of a TV series (and then some). Still, “Pirates” fans are rabid and might enjoy this on some level. For anyone less than devoted to the Cult of Sparrow, stay away. NOTE: A mildly amusing, much-anticipated cameo by Keith Richards as Sparrow’s father is decent enough.