As far as I know, I know that there are three bad endings you could get (there might be more). You would be on the right track on your route if you saw "To Be Continued," at the very end, but otherwise...
Spoilers ahead. Read at your own risk.
1st Bad Ending (Days 4-7)
You do not spend at least three days with the villager of your choice.
2nd Bad Ending (Day 14)
You have one of the felynes stay behind instead of yourself.
3rd Bad Ending (Day 17)
You make too many mistakes in the trial.
A bad ending would be signified by a wall of text against a black background. Not to mention that the overall tone of the text is highly ominous. I should know, since I inadvertently got the second one in a reckless fashion...