The classic Blue Spheres bonus stages from Sonic 3 & Knuckles make a triumphant return. These stages are accessed by passing a Star Post with 25 or more rings. In these stages, your goal is to collect all blue spheres while avoiding red ones. Collecting all blue spheres without touching any red ones earns you a 'Perfect' bonus and a silver medal. Collecting all blue spheres (even with red sphere touches) earns you a gold medal. Medals are used to unlock various extras in the game.
While Sonic Mania celebrates these classic 2D puzzles, Sonic Forces focuses on high-speed 3D action, omitting the traditional Blue Spheres mechanic in favor of modern boost-based gameplay.
While Sonic Mania utilizes these stages for unlocking medals, Sonic Advance 3 previously adapted the Blue Spheres concept as a multiplayer-focused mini-game titled "Sphere Panic.
While the Blue Spheres stages originate from later sequels, they are accessed via the iconic Star Post gates first introduced in Sonic the Hedgehog 2.