This looks fantastic! I’ve been seeing a growing number of tools trying to bring more interactivity to programming tutorials and for good reason. Screencasts are too passive, and it’s easy to get lost halfway through. Books and blogs don’t really show how code evolves over time either.
I’m working on a solution too, called CodeMic [1] where instead of bringing the environment to the web, it brings video and workspace sync into the IDE so viewers can follow along directly inside their own editor.
You’ve done an impressive job integrating everything, including the Console for example, that’s especially tricky to pull off in an extension for VSCode, Emacs, or Vim.