The real-life captain, Anatoly Gushchin, was in his 30s, not an elderly man as depicted. The politruk, GRU officer Vasily Besedin, was the same age. Moreover, the Chief of Staff Josef Avrukyevich (sometimes named Avsukyevich) was on board as a supervisor with a role that has yet to be established, which the series omits.
When discussing the possibility of the submarine being equipped with nuclear weapons, the characters keep referring to signs of radiation from Uranium 238. This should have been Uranium 235 or Plutonium 239.
General Cooper is seen wearing Global War on Terrorism Expeditionary Medal and Global War on Terrorism Service Medal ribbons on his rack. These awards did not exist at the time depicted.