Doesn't RPython do all the same things? Also there are language workbenches (http://www.languageworkbenches.net/) that allow one to get a bunch of things like IDE support and even basic compilers by properly expressing the language syntax and semantics.

I agree there is a lot of interesting stuff going on here but lets not forget the prior art. Even OMeta I think already did a lot of these things way back when. Going further back there's META II (https://en.wikipedia.org/wiki/META_II).

I think building self-specializing interpreters is the main trick. If that becomes easy then a whole bunch of other magic is also possible. But I'm just an amateur so all of this is still very impressive.