Asklemmy

This is a lot, so I'll go through it point by point.

a) Marxism is the ideology formulated by Karl Marx, centering on a Scientific approach to Socialism, analysis of Capitalism along the lines of Marx's Law of Value, and the philosophy of Historical and Dialectical Materialism. Marxism is an umbrella term for the various strains descending from this, the most common by far being Marxism-Leninism.

b) Socialism is an umbrella term for various economic propositions centering on collective ownership. Anarchism and Marxism are the most common umbrellas under Socialism.

c) Leninism refers to Lenin's contributions to Marxism. Often it is used to explicitly reference the aspects of Marxism-Leninism that came from Lenin, such as analysis of Imperialism, though the idea of "Leninism" as a complete ideology is wrong, as Lenin was a Marxist and relied on Marxist analysis.

d) Stalinism usually is a reference to Stalin's stance of Socialism in One Country, as contrasting Trotsky's Permanent Revolution. Stalinism itself is not an ideology, but a policy position that is no longer really relevant in the modern day as that question was for the early Soviet Union. Sometimes Stalinism is used in place of Marxism-Leninism by those wishing to drive a distinction, but Stalin merely synthesized Marxism-Leninism, he considered himself a student of Lenin more than a theoretician in his own right.

e) Maoism, not to be confused with Marxism-Leninism Mao Zedong Thought, is an ideological strain under the umbrella of Marxism that places the Class Struggle at the top priority, rather than alongside the other pillars of Marxism. Examples of those influenced by Maoism include Gonzalo, but not Mao, who was a Marxist-Leninist, his contributions being called Marxism-Leninism Mao Zedong Thought.

2. This is historically and analytically inaccurate, see the previous comment where I answered this more in-depth.

3. The Eastern Front, also known as the Great Patriotic War[n] in the Soviet Union and its successor states, and the German–Soviet War[o] in modern Germany and Ukraine, was a theatre of World War II fought between the European Axis powers and Allies, including the Soviet Union (USSR) and Poland. It encompassed Central Europe, Eastern Europe, Northeast Europe (Baltics), and Southeast Europe (Balkans), and lasted from 22 June 1941 to 9 May 1945. Of the estimated 70–85 million deaths attributed to World War II, around 30 million occurred on the Eastern Front, including 9 million children.[5][p] The Eastern Front was decisive in determining the outcome in the European theatre of operations in World War II, eventually serving as the main reason for the defeat of Nazi Germany and the Axis nations.[q] It is noted by historian Geoffrey Roberts that "More than 80 percent of all combat during the Second World War took place on the Eastern Front". Per Wikipedia.

4. I included those theaters, the combat on the Eastern Front was on an entirely different scale.

5. The Russian Empire refers to Tsarist Russia, not the USSR. The USSR was not an Empire. Again, more historical inaccuracy and failed analysis, see the above comment.

6. Finishing your comment on a racist tirade and calling me a bot for disagreeing with you and backing up my claims with sources is not really something I think of when I think of "left-wing."