Ask HN: Feedback on diagram builder with novelty zoomable UI

This web app combines Sankey diagram with zoomable interface. The reason is that in order to display financial flows - like in the example - you need the ability to display very small and very large elements at the same time. My intention was to build on the familiarity of Google Map interface. How did I do? Do you know how to move around? Are you confused? Any feedback is utterly welcome.

blog.wikibudgets.org/2015/01/sankey-builder-launch.html