Here is the full list of all 8 Shan Gui achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Congratulations! You found the secret bonus content!
Received the gift from the god of the mountain.
You've had a sweet journey with the heroine, right?
Meet with the manager.
Found out the designer of the teahouse.
Meet with the girl.
Here comes the heroine.
To prove this, I clicked "Start Game".