Curved World is a complete collection of the shader bending effects know as:
Exaggerated horizon curve
Horizon bending
Spherical world
Little planet
Cylindrical roll-off
Cylindrical tower
Spiral bending
Inception effect
Twisted corridor
and many others
Shader bending is a special and very effective vertex displace technique for creating bending illusion of a mesh and entire scene without modifying actual and original meshes.
Effect is visible only inside camera and does not disturb game elements like: physics, animation, AI, path finding and other mesh transformations.
Subway Surfers, Minion Rush, Animal Crossing and many others use those techniques for creating world bending effects.
