The USSR did some things Marx advocated for. Namely, state capitalism. Marx thought that in order to bring about socialism, a country's productive forces had to be industrialized to a certain point where socialism could then take over. This is what the Bolsheviks tried to do. The USSR was a planned (command) economy that tried to produce use-values, and not operate according to market functions such as the law of value. In many ways they succeeded but the problems with central planning resulted in defective goods and massive economic waste.
As far as the structure of government, Marx said the state should inherit enterprise, because with a proletarian dictatorship, the working class would be at the driver's seat. This did occur, though arguably the Bolshevik government was elitist and the working class cannot actually be in power. Lenin implemented democratic centralism, where soviets elected members of the national congress and then to the party's central committee, where a majority decision becomes binding upon all members. Democratic centralism was railed by Marx in his lifetime (against Ferdinand Lassalle) because of the use of political parties to achieve socialism rather than worker's organizations.
The democratic centralist form of government is where the most problems occurred. It is the weakest form of socialist organization in terms of preventing bureaucratism and authoritarianism. While Marx thought a transition state would be necessary to defend the revolution from counterrevolutionaries, which might mean some repression, obviously the Soviets went beyond this, especially Stalin. Marx doesn't advocate for an authoritarian state with secret police. The Bolsheviks perverted socialism and strayed from Marx. There are multiple socialists who criticized Lenin, including left-communists and anarchists (the left-communists critiqued his administration from a Marxist point of view).
