Hitler and Eva Braun's wedding is accompanied by Felix Mendelssohn'a classic composition "The Wedding March," but in reality all of Mendelssohn's music was banned in Nazi Germany because he was Jewish.
Hitler's dog Blondi was not killed by Eva Braun, as in the movie, but by Hitler's doctor Werner Haase.
At the end of part one Stalin promises Roosevelt to help him with the war against Japan. This didn't actually happened, at least not during the time of the movie's period which ends at 9th May 1945, as the Soviet-Japanese Neutrality Pact was signed in 1941 and was denounced by the USSR in April 1945. The Soviet Union declared war to Japan later in August 1945.
Stalin barely met anyone from the workers privately and never went into the people, like he does in this movie.
In the movie Hermann Goering invited a British Diplomat to his castle to ask for help from Britain against the Soviet Union. The scene is set after the year 1941, which is identified by the escape of Rudolf Hess to Great Britain on the 10th May 1941. However it is very unlikely that Germany would ask Britain for help, let alone invite a diplomat to Germany, since they were already in war since 1940.