Quite impressive, I once though "building SoCs is no more hard than Lego these days," building an actual core from scratch with HDL is a wholly different level of involvement.
Yes, it's LEGO for anyone with domain knowledge bias.
I would go one further: building a functional, prototype core vs. a marketable core are entirely different beasts given the litany of testing and customer considerations. It's difficult to say what exactly this kid did since the article is light on detail; it could be an achievement.
It's quite trivial to build a simple processor in HDL (.v or .vhdl) because the compiler synthesizes the actual digital logic for you. It's not much different than C or a functional language like Haskell or OCaml, but with considerations of timing and don't cares/high impedance.
PS: s/no more hard/no more difficult/ because "more hard" is always improper when "harder" exists.
