For some reason I felt the plot interesting because of the context, I think I would put in a different margin dictatorship and tyranny, but everything ends in a convergence that shades a precise context that has been lived in the world repeatedly.
The theme of the end of the world and the context of the plot is striking, because of the theme that there is no other place to live. It is something that consolidates a dystopia. : )
I think that this is usually what you do (creating a dystopia I mean) when you want to reinforce a concept and try to make it more powerful, pushing it to its limits to make it more evident to the eyes of everyone...