[AriaMinaei]

This is very interesting.

My question is, could this be implemented on top of an existing editor, like Sublime or Atom?

I'm guessing that that would lower the barrier of entry for most people, including me. (I for example, found the demo video very interesting, but knowing that I'd then have to give up all the customizations I've built up in my favorite editor, I was a bit discouraged to actually try it.)

[comma_at]

Emacs has evil-mode which implements vim's bindings so of course this can be done. Give it a spin though, you might find that some of your customization isn't even needed here, the design is very clean and composable, even more than vim's I'd say.