Sonic the Hedgehog 3 is a 2D side-scrolling platformer. As with Sonic the Hedgehog 2, players can control Sonic, Tails, or both simultaneously. In the former choice, players control Sonic while Tails runs along beside him; a second player can join at any time and control Tails separately.[1] Sonic 3 adds the ability for Tails to fly for a short time by spinning his twin tails like a helicopter rotor.[1] Unlike Sonic, Tails can also swim underwater.[2]
Sonic 3 takes place over six zones,[3] each divided into two acts. Levels are populated with "badniks", robots created by the villain, Dr. Robotnik; Sonic and Tails can defeat them by jumping on them or using the "spin dash" attack, which also gives the character a speed boost.[2] The levels include obstacles and other features such as vertical loops, corkscrews, breakable walls, spikes, water that the player can drown in, and bottomless pits.[4] There is a miniboss fight with one of Robotnik's large, powerful robots at the end of the first act of each level and a boss fight with Robotnik at the end of the second.[5] Reaching a new level saves the game to one of six save slots.[6]