THE UNDOING: A lesson on flashbacks.
This story, as many limited series is, is a whodunit tale. Over six episodes, we receive breadcrumbs and contrasting evidence to take us off the scent of the killer. One storytelling mechanism used is the flashback.
In my opinion, they were overused, distracting, and often confusing. For the first few episodes, we tend to go into flashbacks from our protagonist, Dr. Fraser's POV. Because of this, it seems that she is present in places she shouldn't be and learning information that only we should be privy to. It comes off as supernatural as if Dr. Fraser is psychic (in hindsight of course).
As the episodes went on, we began to seemingly "see" through others' POVs. What're the rules here? It was a bit jarring because this was a strictly A-story series. No other characters had storylines for us to even need to be in their POV, so it felt forced when we saw the truth of what happened that night through someone else's eyes.
With that said, the series could've been done without the ghostly flashbacks that were purely cinematic but didn't necessarily connect to the story and stuck to maybe only the details of that night.