I looked at some of the files in that game and experienced severe pain. Did you know the audio log objects take up like 7gb because the assets are copied in their entirety for each notebook page. So instead of sharing textures for the parts of the notebook each page has its own complete book material in unnecessary resolution. Also pretty sure the audio could be squished down more. Anyway that's just one small part of it. The maps are insanely big in terms of disk size.