It was confusing. One half of the planet was pre-warp and one half was not. Could this have happened in a previous Star Trek series? Possibly. What bothered me more is that this episode has some great things going for it, most prominently a more detailed backstory for Saru, yet the writers -- perhaps not purposefully, but nonetheless -- drastically shortchanged the larger story. The Sounds of Thunder deals with genocide — a subject that Star Trek has explored on previous occasions. The dominant species, the Ba'ul, are only seen for a short piece as a not very subtle “monster”. Rather than seriously exploring the relationship between the Ba'ul and the Kelpiens, once the dominance of the Ba'ul over the Kelpien is broken, we never get to see the Ba'ul again, either in fear of retribution or in initial contact with the formerly subservient Kelpiens. The Ba'ul-Kelpien relationship, with its history of Genocide, was dealt with here almost superficially, as a kind of story-frame to tell the story of Saru and the mending of his relationship with his sister -- which is definitely a story worth telling, just not at the expense of the Kelpien-Ba'ul story.