Just finished reading every part. This felt a bit generic overall. The siscon/siscest stuff was just creepy, and the novel feels weak in the first half. Most characters were shallow and not very well developed, except for the Redge who had the best characterization out of everyone. The author talks about doing more with this world, but I'm not really too eager to see more.
On a positive note, the action scenes were well choreographed and the novel does admittedly get better in the second half. The art was definitely good, and a highlight for me. You can tell this was Atsui's first novel, but like @Demelza, I would be interested in seeing the author working on something else. I think he had some potentially interesting ideas, despite a rushed execution and a lot of ideas crammed into one novel.
Some typos I noticed:
part 4: it should be 1001st, not 1001th
part 5: “playtme” @10%, "It that hit her” instead of "if" @ 93%
part 6: No ending quotation mark after Yukihime says “Kokuya… @ 56%