Sonic & Knuckles is a side-scrolling platform game that continues the events of Sonic the Hedgehog 3. Sonic seeks to prevent Dr. Robotnik from repairing the Death Egg and obtaining the Master Emerald, while Knuckles attempts to protect Floating Island. Players can control either character through a series of zones, collecting rings and Chaos Emeralds while defeating enemies and bosses. Knuckles can glide, climb walls, and break certain obstacles, while Sonic can use abilities granted by elemental shields.