An analysis by an American Marxist professor from 1995, after reviewing the Secret Soviet Archives:

The worker - having been stripped of personal ambition and revolutionary fervor - is compelled to comfort the bourgeoisie at the expense of his home and dear mother. The bourgeoisie seeks to muddy the waters and create an identity full of illusions and fear, such that the worker conflates the happiness and goals of his boss as his own. Of course, the bourgeoisie is under no such illusion, for if the worker was happy - truly happy, that is, such that he is not starving and dreading over tomorrow’s rent - it would be the death blow to the exploitative and cruel ideology that supports his decadence and comfort.

Apparently it’s a parody of the short film Стеклянная гармоника, or The Glass Harmonica. It’s very modernist, kind of like an animated Guernica in places, and with a score equal parts avant-garde like George Crumb’s Black Angels or Penderecki’s Threnody for the Victims of Hiroshima, and some parts more akin to a Romantic era symphony.

The video I linked to also insists that it was a secret criticism of the lack of spirituality in the USSR which seems like absolute bullshit to me as it was hardly subtle about the spiritual aspects, and if it had been intended as a criticism, it would almost certainly have been banned (not to mention the fact that there is a kind of spiritual aspect to communism which is divorced from religion, and that’s what I believe the film is getting at). Here is a better quality version without English tranlsations of the text at the beginning.