The Nazis never rise to power

In our timeline a notorious fascist ideology, National Socialism (Nazism) takes power in Germany lead by Adolf Hitler which lead to the deaths of 17 million people across Europe from 1933-1945. However, in this alternate timeline the communists take power in Germany forming a coalition with the Weimar republic with Ernst Thalmann as the chancellor and Paul Von Hindenburg as the president until 1934 when instead of Von Hindenburg dying of natural causes as he did in our timeline he is arrested, put on trial and executed in a purge by the communist party which eliminates thousands of political opposition including Adolf Hitler. After this the German Democratic Republic is formed with Thalmann with the title 'Führer der Menschen' or 'People's leader'. The GDR forms an alliance with the USSR in 1934. On the outbreak of the Spanish civil war in 1936 the Germans and Russians send direct support to the communists. With the British, French, Italians and others forming an alliance against the communists and fighting them in Spain, World War Two breaks out. Poland, one of the allies, is swiftly conquered by German and Russian forces. German troops march into Belgium and begin marching towards Paris. Allied forces attempt an escape from Continental Europe to Britain in 1939 as they did in our timeline in 1940 except this operation fails and in January 1940, after long struggle, Britain and Italy signs an armistice with the Communists. The Spanish Civil war, still going on is won in February 1940 and only those countries who remained neutral remained free. With VE Day celebrated on Valentines day 1940 Stalin now turns his eyes to Asia and invade nationalist China and the Japanese empire in what becomes known as the first trio war. This is much to Germanys's disapproval and relations begin to falter between the two by December 1940. The war is prolonged until February 1941 with China under communist rule and an invasion of Japan in place but it is stopped when a ceasefire and an official end to the war. Germany is supporting the growth of communist movements and governments in Europe's former colonies. USSR and German relations again falter in 1942 as WW2 is again recalled as an invasion of America happens. It takes much longer but in 1944, both the USSR, America and Germany develop nuclear weapons. A second trio war is launched when Germany spontaneously attacks Russia in 1944 with Nuclear warheads begin launched across the world. Civilisation is destroyed and Man has to start again. In 2014, the situation is a lot better with full on communities and laws being built but there are still alott of challenges in a post apocalyptic world. This is just one of the many scenarios or what could happen if the Nazis never rose to power...