Awesome! (For some reason, the demo gif doesn't display for me in Safari, but I can see it in Chrome/Firefox.)
I feel like this sort of thing could really be an essential tool in teaching programming. I've been working on a somewhat similar project for visualizing execution of javascript code (but it works by instrumenting the code, rather than interfacing with a debugger, so that it can all be done in the browser), which I'm hoping to release soon.