A shortcoming in the opening that future films learn from...
Without bad-mouthing this film because I know that silent films were the infancy of film-making and therefore shouldn't be begrudged chronological short-comings I would like to point out how film-making creates better drama by having chronology work differently in later films.
The movie begins with the beaten-down working class trudging miserably off to their gruelling routine keeping the city glowing and then the scene shifts to the shining, gleaming city and the privileged upper class enjoying the fruits of the working classes toil.
For more emotional impact and drama later films would open up with the shining city first and its happy utopian society. THEN the hero would go underground and see to his horror the misery of those slaving away to keep him in luxury.
This way the let-down of the revelation that things are not so great is more shocking.
We always improve things by learning from imperfections of previous works.