When/how/why did the Bolshevik revolution go from being a movement for the people of Russia to becoming a dictatorship arguably worse than the Monarchy they over threw?

My in depth knowledge is a little vague so any Russian historians here let me know. How did Lenins vision of Communism go from his theories of openness and equality to the extremely secretive and one man rule that came to define what would become the Soviet Union. Also, how did this happen? And who were the main players to nudge the fledgling revolutionary government in.this direction and why didn't the Russians themselves intervene when they had the chance?