How Cliffhangers Go Wrong (and Right!)

Spider-Man: Across the Spiderverse ended on a surprise cliffhanger, prompting many folks to scream in agonized delight about how they wanted more. Is that a good cliffhanger or a bad one? And what are some examples from the past that have worked? Does the sequel to the cliffhanger have to be good for the cliffhung movie to work in retrospect? Or can tim…