What is an unsatisfying turn of events that serves as a substitute climax called?

An unsatisfying turn of events that serves as a substitute climax is termed an anticlimax. This literary device occurs when a story builds up to a significant moment that has the potential for high drama or excitement, but instead leads to a disappointing or trivial conclusion. An anticlimax often deflates the tension that has been built up throughout the narrative, leading to surprise or even humor rather than the expected emotional payoff.

In contrast, a cliffhanger leaves the audience in suspense, typically at a moment of high tension, inviting them to wonder what will happen next. A resolution refers to the conclusion of a story where the main conflicts are resolved, which is considerably different from an anticlimax. The denouement is the final part of a story, where any remaining issues are resolved and the story is wrapped up, but it comes after the climax rather than serving as a substitute for it. Thus, the direct contrast between the anticipation of a climax and the letdown of an anticlimax makes it the correct term in this context.