Insidious: Chapter 2 is a puzzle movie with too many unnecessary pieces and not enough essential ones, but it's superior to its predecessor in a few basic ways.
It's not gory, but relies on ceaseless weirdness with scores of jump scares and even an odd Back To The Future 2-style subplot that's undeveloped yet still adds to the overall sense of crazy. Love or hate it, this is pretty effective modern scare cinema.
Characters in Whannell/Wan screenplays speak with the first-draft expository bluntness of a cheap '50s thriller, letting the characters step on some of the best reveals.