Character upgrades are permanent enhancements that unlock new abilities or improve existing ones. These are typically found in hidden item boxes within specific stages. For Sonic, the Light Speed Shoes (City Escape) enable the Light Speed Dash, and the Bounce Bracelet (Pyramid Cave) allows for a powerful downward bounce. Shadow gets the Air Shoes (Radical Highway) for Light Speed Dash and the Flame Ring (White Jungle) for a stronger Homing Attack. Knuckles finds the Shovel Claw (Pumpkin Hill) for enhanced digging and the Air Necklace (Aquatic Mine) for underwater breathing. Rouge obtains the Pick Nails (Egg Quarters) for enhanced digging and the Treasure Scope (Security Hall) to reveal hidden items. Tails receives the Booster (Mission Street) for extended flight and the Laser Blaster (Eternal Engine) for stronger attacks. Dr. Eggman gets the Jet Engine (Iron Gate) for extended flight and the Large Cannon (Cosmic Wall) for stronger attacks. Finding all these upgrades is essential for 100% completion and mastering each character.
