Flying Fish World (known as the "Revenge Building" on its map) is an area accessible from the Museum and was made to replace Concrete World.
Features
It contains green blocks with doorways in them and many plants in pots scattered around the area (that sometimes glitch if you ride into them with the Bike). Goldfish are "swimming" in the foreground, and the area seems to have a space-themed background.
It works in the same way as Concrete World did in
previous versions i.e. you go into one doorway and come out another. Sometimes you have to go back through the same doorway to get farther.
There is one doorway that is boarded up. If you chainsaw it, you can go through it and see Smile-san.
There is another doorway leading to Urotsuki's Dream Scene. When you go through it, you will go through a hallway similar to the one pictured right, although it changes every time you go through it. Sometimes, if you're
lucky, you will get to see Nichiyo-san in her sprite form.
Urotsuki's Dream Scene is simply a body of water (probably a lake) with some sort of diving block that you can sit on during a sunset. You can see the Twin Mountains in the background.
The Spacesuit effect can be found in this world somewhere near the top of the world. There is also a portal to the Urban Street Area (that was previously in the Teleport Maze).
There are some unfinished areas that you can access from this map. Interacting with a cluster of empty pots takes you to an area with spining clocks, and interacting with a plant in a pot takes you to a monochrome room similar to one from
Yume Nikki. Interacting with the big eye on the wall causes a full screen event to happen.