The only thing missing was some more visualisation of the core meltdown process aka CGI. Like how did the elephant foot form or the graphite tips cause the explosion in the first place. However, the lack of special effects doesn't affect the impact and tension of the show at all. It would just be nice to have had. Storytelling and acting is probably amongst the best in the last decade. Wise choice to not impose fake russian accents, it allowed the actors to give much more depth to the characters they deserved. If people think the series doesn't pay enough tribute to the heroic actions of the workers, you're dead wrong.