I really liked the interaction, but thought that it could also be used for chapter navigation.
I also make use of Lectora’s Status Indicator Objects for at-a-glance progress tracking on a chapter progress page. The five available chapters culminate in a final sixth “completion” chapter… kind of like Voltron (or Captain Planet, or the Megazord) the user is required to complete all five chapters to access the final chapter. Variables track end-of-chapter actions to make sure the user has viewed all of the content. These variables are tracked on both the chapter progress page AND on the next button that would progress from the End of Chapter 5 into Chapter 6… in case a user is trying to skip to the end.
Hopefully this will be of use to other developers. Feedback is always appreciated.