Hidden World (ヒドゥンワールド,Hido~unwārudo?) is the eighth world in the Wii U version of Sonic Lost World. It is unlocked after finishing the previous world, Lava Mountain. Unlike other worlds in the game, Hidden World has abstract backgrounds and does not appear in the game's storyline. Because each of the Zones in this world play very differently to the earlier worlds, it is believed that Hidden World's zones contain concept ideas that did not make it into the main game.
The player begins on a large cube with a time limit of 30 seconds. Each side of the cube consists of 49 red, blue, orange, yellow, white and green tiles. A box with eyes is located on each of the cube's six sides. The box, after a few seconds, turns on its side, flipping over several tiles, which could hurt Sonic should he step in the way. Sonic destroys the box with a Homing Attack in order to save an animal, add ten seconds to the time limit, and continue to the next side. This continues until Sonic loses all his Rings or runs out of time, in which the zone is cleared and Sonic's score is tallied.
In this zone, the player controls Tails in the Tornado, with Sonic standing on the biplane's wing. The player must steer around Badniks (most of which appeared in Sky Chase Zone from Sonic the Hedgehog 2) and obstacles in order to make it to the finish, collecting extra time and speed boosts along the way.
In this zone, Sonic is on foot, and his objective is to progress through the level until he reaches the end. The level is styled like the inside of a tube, and the platforms, when non-metallic, are a series of adjacent tiles lined with cyan or yellow on the edges. Cyan tiles grow smaller when stepped on and yellow tiles move. Some obstacles break the yellow tiles when they touch. Also, this level is techno themed.
The fourth and final zone starts out with Sonic on a bubble with a spike ball inside of it. There are many of these bubbles throughout the zone and they each have their own gravitational pull, like planets. When Sonic jumps from these bubbles, they pop and shoot the spike ball in the opposite direction the Sonic jumps. After getting a certain distance, there will start to be little orange and white creatures in some bubbles instead of spikes. These creatures will follow Sonic and try to bite him. After continuing on, the music speeds up and a large Baku Baku will appear behind Sonic and he has to blow spikes into the creatures mouth until he is defeated.