.
.
.
.
.
.
.
I want to clarify that I don't think the puzzle is flawed, in a broken sort of way. My criticism was regarding the much higher difficulty for it. Perceived "difficulty" is individual and can vary a lot, so fair enough if others didn't have problems with it. Props to you for figuring it out quickly! I can only speak of my own experience and I felt it was much harder than the rest of the game and stopped the progress as a rather abrupt obstacle.
My reason for suggesting renaming "K" is that it would reduce the ambiguity of what the filename for the final scene could be. All other scenes follow the same pattern with numbers for the people, so allowing a letter in there makes the search-space even larger. You seem to argue that "K" can't be renamed because there's a fixed rule about having the characters numbered in a specific order, which isn't really the case. It's true that the numbering follows the apparent order in which they die, but then Hobbes wouldn't really be number 1 since he never became part of the chain. Katherine would be 1 by that logic.
I guess the biggest problem for me was to realise WHEN the scene took place. I was pretty sure it would take place on 27 since there were hints about "completing the chain". The clue about "distant thunder" was too vague for me to understand that it was the same "death sound" that had been heard for the other deaths. I was also confused by the "one death doesn't quite fit the pattern" clue, which made me start theorising that maybe one of the earlier deaths were faked à la "And Then There Were None". Which made the number of possible final scene permutations enormous, when I didn't know WHEN, WHO and maybe not even WHERE it took place.
Anyways, I still think it would help to make the filenames consistent by only using numbers for the characters, but the biggest improvement would be to make it clearer that there's a similar thunderclap sound in 25-AT-1.