Sonic 3: The Story of Knuckles, known as Knuckles the Echidna in Europe and Japan, is a 2023 3D platformer/action title that continues after the events of Red the Dingo. Oddly enough, although titled as Sonic 3: The Story of Knuckles in the US, you play as Knuckles until the end of the game, when you play as Sonic for the final 2 levels of the game to free a captured Knuckles.
A robotic version of Sonic, known as Buzzsaw, attacks Angel Island, so Knuckles, as guardian of the Master Emerald and the island, must defend his home. But once he's captured, Eggman reveals his secret weapon....
A lush, green forest with pools of water throughout
Knuckles' personal forest of giant bouncy mushrooms, planted on rolling green hills
Snow covered mountains known for their slick slopes
An area full of hot magma and jagged rock underground
Ancient home of the nearly extinct Echidna. This is where Knuckles is captured. Sonic and Tails land, see the Death Egg rise, and run to the sanctuary as the island falls
Emerald Alter Sanctuary
A peaceful white marble structure surrounded by bouncy clouds, leading to where the Master Emerald once was. Sonic and Tails jump on a particle accelerator and get warped up to the Death Egg
Sonic and Tails encounter Buzzsaw, free Knuckles, and work with him to defeat Eggman and return the Master Emerald to Angel Island.