The player controls the titular Sonic the Hedgehog to collect the seven Chaos Emeralds, free the animals trapped inside robots, and defeat Sonic's nemesis, Dr. Ivo Robotnik ("Dr. Eggman" in the original Japanese release) The game is split up into zones, each of which is split into three acts.The player must navigate through each zone to progress. In each zone's third act, the player confronts Dr. Robotnik, who rides a vehicle. After completing the sixth zone, the player continues directly to the Final Zone for the last encounter with Robotnik. The player is given a certain number of lives, which are lost when Sonic collides with hazardous enemies or objects, falls off-screen, or exceeds an act's ten-minute time limit. If all lives are lost at any point in the game, the "Game Over" screen will appear, at which point the player can return to the beginning of the act with three lives if the player obtains continues from Special Stages.