Shostakovich traded in his overt comedy for a thick slide of wry. There is humor in his later music, but he kept it under cover and it's more enigmatic. That Rossini quotation in his last symphony, for instance - it's the opening phrase of the "Lone Ranger" galop from "William Tell". The resemblances in New Babylon to his later symphonies show that he really retained the same idiom throughout his career - there was a personality there that couldn't be repressed, and the darker side was there from the beginning, too.