Actually, Karl Marx and Friedrich Engels adopted the term "dictatorship of the proletariat" (originally coined by Weydemeyer) to explain their vision of government in a socialistic society supposedly evolving towards communism.
This murderous system has been tried extensively during the 20th century and is still being tried in North Korea and China. Even now, China has over 1 million Muslims in concentration camps. All in the name of Marxism.
Marxism is a flawed philosophy and a catastrophic failure. In praxis, It replaces established elites by a new one - the communist party: Intellectual bureaucrats that claim "true marxism" was never implemented, but it will work this time... as soon as they murder all that oppose their new interpretation of communism.

Over 100 million murdered by communism in the 20th century is enough evidence that communism doesn't work.
Furthermore, the idea that they were not really communism is very arrogant. A person making this statement means that Stalin, Lenin, Trotsky, and Mao didn't know what they were doing but he/she knows. Just preposterous.