The last puzzle in this series of Flashbacks is the hardest of the lot. Only 1 solver (Thomas Snyder) managed to solve it. Nowadays I use a computer when writing a difficult puzzle with many deduction-paths, but back then it was all grid paper and a lot of erasing. Because of the very-restricting nature of the type, I don’t think Akasuke will see any of its siblings soon.
So here is the devil that hardly anyone solved. Have another go at this in an untimed environment.
Akasuke: Fill in the grid of shaded cells with the listed numbers. Afterwards, the numbers become Akari clues, which are used to solve Akari in the usual manner.