You might also look at the Simple Lesson Module from Richard Jones
https://www.elearningworld.org/author/rjones/
That doesn't implement question based branching at the moment but the author seems to have been thinking about it because there is a branch that refers to question branching.
https://github.com/richardjonesnz/moodle_mod_simplelesson/tree/question_branching
For me one of the issues with this is to make the selection of the next question and the interface to setting it up easy enough for normal people to understand. The problem is that if you have the knowledge to build something like this and are reading this thread then you are probably not in my definition of normal (grins)