Yume Nikki is a game developed by Kikiyama and released in June 26 2004 on rpg maker 2003 and over the pass 20 or so years his game as created a large cult following. In Yume Nikki you play as a girl named Madotsuki. Whatever you do you can't go out of your room, Madotsuki nods a no when trying to open the door outside her room. Despite probably being a shut in you can explore something else much cooler, her dreams! When you press the action key when next to her bed you nap and spawn into the Nexus
The nexus serves as the main hub and connector to all the main worlds in the game