A large set of greenery ruins set flying high in the clouds amongst dangerous gusts of wind and a lethally violent tornado, Windy Valley is located inside a cave within the Mystic Ruins. The level is split into three main parts: the windy hills at the beginning, the tornado, and the aerial spiraling tracks. Sonic goes through all three, while Tails goes through only the third, and Gamma goes through only the first.
In Sonic's story, Windy Valley is the second level. Here, he and Tails attempt to track down a Chaos Emerald to stop Chaos from collecting them all. For Sonic, he has to proceed forward through the stage until he reaches a tornado section, where he must go upward through to exit. Afterward, Sonic will enter a sky section where he must run down several twisted platforms to reach the Chaos Emerald.
Windy Valley is Tails's first level, where he must race Sonic from the section after the tornado to the Chaos Emerald. Interestingly, because the whole level moves downward, Tails can fly from the beginning to the end of the level without touching the ground using the airborne Dash Rings.
Windy Valley is Gamma's third level. Here, Gamma searches for E-103 Delta to free him after being banished from the Egg Carrier. Like his other levels, enemies and other structures must be destroyed to increase the time limit.
Windy Valley is the only level that went through the biggest visual changes and beta elements between the announcement of the game on August 22, 1998 and its release in December. Though still broken up into three parts, the layout and textures for each were completely redone. Although it was not included as a playable stage in the Autodemo, there are still remnants of the early model of Windy Valley in its game files that were shown in the prototype images.