Could you elaborate on those features? From the top of my head, those are: nested functions — those always were of dubious usefulness compared to the implementation difficulties needed; labels are actual constants, so computed GOTO is available — that's definitely a feature standard C still doesn't have; manifest constants — this one is Ritchie's most baffling omission in the language; multiple assignment — it's not actually parallel so merely a syntax nicety (with a footgun loaded); valof-resultis — while very nice, it's also merely a syntax nicety, "lvalue := valof (... resultis expr; ...)" is the same as "{... lvalue = expr; goto after; ... } after: ;".

What else is there? Pointless distinction between the declaration syntax of functions and procedures?