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]
As with previous Sonic games, Sonic 3 uses rings, scattered throughout the levels, as a health system; when the player is attacked without rings, is crushed, falls off-screen, drowns, or exceeds the act's ten-minute limit, they lose a life and return to the most recently passed checkpoint. Dying with zero lives gives the player a game over. The levels also include power-ups in television monitors that, when hit, grant the character an extra life, temporary invincibility to most hazards, a number of rings,[7] a shield that allows them to breathe underwater, a shield that allows them to withstand fire from enemy projectiles, or a shield that attracts nearby rings.[8]
Sonic 3 contains two types of bonus stages. When the player collects at least 50 rings and passes a checkpoint, they can warp to the first type,[9] which involves bouncing up a gumball machine-like corridor to earn power-ups by hitting a switch. Both sides of the corridor are lined with flippers, which disappear when the character bounces on them, and the switch drops when both flippers supporting it are removed. The corridor's floor contains a bounce pad, which also disappears after one use; falling afterwards causes the player to leave the stage with the most recent power-up collected.[10]
