:D
What exactly was the quest you were locked out of? And what kind of hint would you suggest, considering I didn't want to outright spoil the surprise?
I'll try to be cautious to not spoil it for people who are about to play it, but basically.
The quest was bringing back the villagers. I was in the middle of that quest when in the 9th day out of nowhere the surprise happens and no matter I do it or not, I can't finish the villager quest afterwards. And since it saves in the night, I didn't think that'd be a point of no return for the game and got locked out of it because I saved in the same slot.
Of course I could still follow the story as normal to the end of the chapter but I kind of left feeling bad because I wasn't able to rescue them all at the end.
I would suggest triggering that surprise once the villager quest has been completed so that people don't feel like it was a left out story plot.
I see! The reason for that is, the villagers can't possibly be brought back after the end of day 8. This is due to spoilery reasons that I assume you already know about, but if not, there is a time limit. Completing the villager quest, while definitely a significant quest, is not a "Main" quest that you must complete to advance the game^^
In other words, your experience was one of the intended experiences. Sometimes you won't manage to accomplish everything, and that's okay.
What I will do is, add a clear warning that time may be of the essence in some situations.