Very cool. I really like the idea of implementing higher level features as extensions on top of a smaller core. I wish real scripting languages like this were more common and in use. Lua comes to mind when thinking about a generic scripting language, but even that is not that widespread.
I think "implementing higher level features as extensions on top of a smaller core" is a hallmark of the Lisp family. Check out Fennel [0] or Janet [1] for two different approaches. On top of everything, Fennel is 100% Lua-compatible.