I think this is an interesting premise and for 72 hours you really got a lot done!
That being said, I have some feedback on the execution. For context, I was streaming this to a friend who loves creepypastas.
From an environment design perspective, I found myself asking why the area was so cluttered with items. Wouldn't it be better to reveal them day by day as they became relevant?
We both feel like the reveal would have been more impactful if there had been more to build up the illusion of a peaceful town life. If we could get to know the other residents or engage in other activities, I think the player would have more of a bond with them and so it would be more shocking when something happens to them.
Also, it's possible to miss the dead body clue (or perhaps it doesn't spawn for everyone?); I found out about it from the comments section, and I did attempt to explore the entire map. Neither I nor my friend noticed it in my playthrough.
My friend said the danger was too obscured for him to understand what he was supposed to be scared of: did they do this to themselves? Is there some kind of monster that made them do this? What does the danger intend towards the player character? After all, now that everyone is dead, what can they do to hurt us?
He also thought (once I told him about the dead body) that there isn't a narrative justification given for why the previous resident died early if the point of the Harvest Festival is that everyone dies by suicide. If, for example, the previous resident had said "you should get out of here, I'm leaving tomorrow" on Monday, been missing on Tuesday, and showed up in the water on Wednesday, then we as the audience would have understood this was retaliation for trying to leave and we would've felt trapped.
This has a lot of potential if you choose to expand it—I'd love to see more of these characters and the world they live in.