You must be watching this with the right group. I believe the translation may have been consistent, but I stopped paying attention to it and naturally became gripped with the original dialogue as each scene dropped a heavy ball on my very limited knowledge of the history of the last half of the precious century.
If I had read on the history more I might have known what I got myself into. The intensity of the depiction really got me passionate about this very uncertain piece of our recent times. You must see it. I expect more to come from the effort to dig deeper into a very molten ball of lava which had entwined the political shaft unto the core of the modern Korea.