[eris_sama]

I'm assuming no spoiler tags are needed since this thread is obviously for people who know, who have seriously thought about it, or who want to be spoiled. I have seen the entire series and read all the above threads. Unfortunately I will never be able to play the game as I know absolutely no Japanese. It seems that not everything is explained in the game but here the main elements as I understand it.

Dam war - Cause a rift in the village with the Sonozaki family on one side and the Houjo family on the other. The latter was ostracized. The Sonozaki family was involved in the kidnapping of the minister's son which forced him to stop the project.

Death of foreman - It seems that who killed the foreman is not that important. All but one culprit was caught. He was probably killed by crazed villagers against the dam, under the influence of the pathogen. The missing culprit was taken by the organization.

Death of Satoko's parents - The fact that it happened on the same day appears to be a coincidence. It happened on their vacation. Satoko appears to be responsible as she hated her stepfather. She may have intentional pushed him over and her mother died trying to save him.

Death of Rika's parents - The fact that it happened on the same day appears to be a coincidence. The priest might have just succumbed to stress because of the festival preparations. The mother appears to be unstable and committed suicide, possibly afraid of being spirited away after her husband's death.

Death of Satoko's aunt, Satoshi goes missing - I believe Satoshi did kill her, but he was taken by the organization.

Death of Tomitake, but not Takano - As soon as I read there was a mastermind, I suspected Takano. A fake death always happen in a mystery and hers seemed the most like since positively identifying a burnt body is difficult and requires dental records.

Dr. Irie, Tomitake and Takano were working for the military. There's something about the villagers they are investigating that has to do with a virus or some pathogen that lives in the villagers. When this pathogen becomes active, the host suffers from delusions, paranoia, increased sensitivity to the spirit world, and finally explodes into violence. The military might have been looking into harnessing this pathogen for biological warfare purposes. They wanted live specimens when the pathogen is active. They may have developed an innoculation against it but I don't think so. I think the hypodermic needles probably contains a sedative, either for the organization to capture a live specimen or in the case of Rika to subdue Shion. Takano fakes her own death to pursue her own ambitions.

Rika is the main carrier of the pathogen. She is immune to its affects and her presence can inhibit the pathogen. Upon her death the villagers may all go insanely violent. That is the excuse for the elimination of the village.

Oyashiro is not a hideous demon but a cute creature who is trying to help Rika live past June. There's not much she can do but reboot the world. She's the one who haunted Keiichi and probably others who sensed her presence under the influence of the pathogen.

Each time the world reboots the same basic events happen but among the group of friends they take turns being the victum or villain. Rika dies each time either killed by Takano or suicide or some other way. She retains some of her memory but not of her death. The worlds continue their course after Rika's death. It seems Oyashiro is trying to find the world that will allow Rika and her friends to live.