Steamlyannaya Hamonika (1968) depicts the isolation and brutalization of humans in modern bourgeois society. Although being broadly in line with other art-as-propaganda of the era, censors felt it could easily be read as a criticism of the party, leaving this subversive short as the only animated film to be banned in the Soviet Union.
An analysis by an American Marxist professor from 1995, after reviewing the Secret Soviet Archives: