The war ship "Karl Liebknecht", that was delivering food from Petrograd in the movie looks nothing like the real ship, especially since the real ship had 3 chimneys, while the ship in the movie is clearly a motor based ship.
In the movie Ernst Thälmann and his comrades were still in the army of WW1 when the Kiel Mutiny was announced. In real life while the mutiny began on 3rd November 1918, Thälmann resigned his army duty by not returning home from a holiday in October 1918.
Wilhelm Pieck did not attend the 3rd congress of the Komintern 1921.