It's a tricky thing to carry off a story spanning thousands of years in a sharply limited word count, and I appreciate the adroitness with which you pulled it off.
What I really liked was how, with only the paragraph or so of lore in the OPR army books as a guide, you've managed to put a very compelling and wholly coherent spin on the ideas and imagery from the setting that inspired Grimdark Future - very well done.