Very interesting user interface concept, and smooth implementation. It's weirdly intuitive, like navigating on the surface of a sphere, or zooming in/out of a kind of spherical perspective where things that are further away are smaller in size. I had difficulty at first reaching some small clustered points, until I got the hang of it.

An idea that came to mind is that maybe some shading would help, with closer areas brighter and more distant areas darker. Or, like another comment said, an option to show/hide a grid.