Cosmic World was an area reachable from the Old Train Station. It was removed from the game in version 0.113.
Cosmic World was an area immediately recognizable for its strange and garish colors, causing it to stand out compared to the surrounding worlds and other works of its developer. The islands form a massive archipelago that is notoriously difficult to navigate due to the cluttered objects and lack of visual clarity. Two unreachable NPCs and a nearly invisible Vending Machine could be found here.
You started off from the balcony of a building with a stairwell leading down. East of the entrance (accessible by travelling in a spiral) was a dark blue building which leads to a dark room with bones attached to the walls, a bench and a lamppost, and a rainbow flower on the ground. Stepping on said flower and facing the wall, you could chainsaw it making purple "blood" splatter. Interacting with the box near the bench would show three kanji written in an old-fashioned style. The text reads「白昼夢」(daydream). After using the box it was possible to see the text by accessing one of the books in the lower section of the Library, the one from the second bookshelf on the left. By travelling south from this building and eventually east before you'd hit a particularly narrow patch of island, you could find a forest area with another brown rusty building in the center. This building led to the Square Ruins.
Using the Marginal effect here made the world turned darker and gray-scale. In addition, howling with the Wolf made the ground flash faster, and lighting up with the Haniwa made the ground flash much faster.
Nexus → Red Streetlight World → Gray Road → Grass World → Green Neon World → Construction Frame Building → Cog Maze → Forest Pier → Abandoned Factory → Arc de Pillar World → Mansion → Deserted Pier → Deserted Town → Chaotic Buildings → Transmission Tower World → Complex → Old Train Station → Cosmic World