The Never-Ending Hallway is an area accessible from the Bowling Zone.
Features
This hallway loops endlessly, as its name suggests. It contains several windows with silhouettes of dark figures in them. Some have small handles on them which, if you interact with them, open up to reveal some blue and purple eyeballs.
When you first enter, a shadow lady is seen walking to the left. The hallway gradually becomes desaturated, and a copy of yourself appears and walks to the left. At this point, if you go to the right, your copy will come after you. If she catches you, she will send you to a seccioned off area of Yukata's map in the Invisible Maze.
After you have passed the smiling man, you may come across two windows with both silhouettes and a handle. Interacting with it takes you to the Art Gallery. You may also come across another window which is entirely black. This links to a room that closely resembles Madotsuki's room from Yume Nikki. If you stay for too long in this room, the screen will show only static for a few seconds, and you will be send back to the Never-Ending Hallway.