First, let me say this is a beautiful report. I love the idea of the info pages pop-up and am going to incorporate that into a project I am working on. Now for the feedback.
1. Turn off the visual headers for buttons and slicers. I think they don't add anything and break disrupt the visual flow of the report.
2. On the Measurements page, the Unit slicer hides the visual header buttons for the matrix so you can't use the drill feature.
3. The Further Study bookmark points to the About page.
4. Shrink the bio on the about page just enough to get rid of the vertical scroll bar.
5. On the quizes, put an empty button over the text that appears in the bottom right when a selection is made and link the bookmark to QuizAnswer to that button. Then change the text to "Your answer is X, click here to see if you are right!"