TSH and DDLC (Doki Doki Literature Club) Parallels
This might be a bit of yelling into the void, as it's a bit of a niche connection. Still, I just finished TSH and could not shake the feeling that the second half of the book felt oddly familiar.
Later, it dawned on me that it's very similar to the game Doki Doki Literature Club! Obviously, DDLC came out long after TSH, and it's unlikely that it's an intentional reference, but I thought the trope was interesting.
Notably, both media have a "mastermind" (Henry / Monika) that, after an initial catalyst death (Farmer or Bunny / Sayori), drives the other characters into madness. Most interestingly, both involve the already bad traits of the characters getting amplified to an unbearable degree. Figured it was an interesting comparison and worth sharing!