It's a movie set in a forest where people kill themselves. What more can you ask for?! Plus adding to Japan's own fear and urban legends regarding it.
The quiet shots while Sara and Aiden just wander through forest are pretty unnerving, hitting Nothing Is Scarier levels.
Hoshiko. Even among the movie's many shortcomings, Hoshiko stands out by breaking the typical mold of a Yurei.
Any of the scenes where Sara's in the forest, especially with the "It's all in your head" moments leave you wondering if Sara is just imagining everything as everyone told her it'd be the case.
The ending. After Jess is found and everyone leaves, Michi sees "Sara" hiding in the shadows. The look on his face pretty much sums it up.
