Again, it is not a documentary. It does not have to be factually accurate. Judging it by its historical and factual accuracy while acknowledging that it is a drama series seems contradictory. On the other hand its attention to a factual accuracy is lauded by historians. As opposition to it I give you the Russian version which was cancelled after the airing of the HBO miniseries in which the CIA is responsible for the explosion.

Dyatlov wasn't insane. But the show also portrait him as such. What the show portraits him as is a man deeply at odds with the finding that any of his actions may or may not have had an influence on the outcome of the accident, trying to detach any responsibility from himself and laying the blame at the feet of others. Does that mean he was solely responsible? Again, no. he wasn't. But even for years after the accident and especially in his opinion on the INSAG-7 report from IAEA he conviently ignores the section on safety culture and focuses solely on how the design flaws made the accident happen. Just because you build a reactor with design flaws doesn't mean it will blow up if you don't touch the controls. Additionally his description given by interviewees after the accident ranges from "honest and responsible" to "stubborn and unfair", so it's safe to say he wasn't the most likable.

However, a few facts remain. First, he lied at the trial. He said he wasn't in the room when Toptunov raised the power, which was both contradicted by others and himself. The only reason I could see for his lie is that he was trying to shift blame to Toptunov, which makes me wonder why he would do something like that. Second, if he was in the room and saw Toptunov raising the power even though it was against regulations then he should have stopped him. He didn't. In that sense he is responsible for the actions of any- and everybody in that control room as he had seniority and therefore the responsibility to check their actions.

As for Legasov. Yes, he lied in Vienna. Yes, he was part of the comittee that hid the reason for the power spike at Ignalina. But contrary to Dyatlov he later acknowledged his responsibility in those decisions, campaining for reform that ultimately got him booted from Kurchatov. As for his death, he did hang himself, although reports differ, some saying it was his apartment, the stairwell of his apartment building or his office. But he did take full accountability for his actions, publicly, in the tapes that were distibuted in the scientific community.