The game is divided into six zones ( Green Hill , Marble , Spring Yard , Labyrinth , Star Light , and Scrap Brain ) , each with its own visual style and enemies . A player must navigate through each zone ( subdivided into three acts ) to progress . At the end of each zone 's third act , the player confronts Dr. Robotnik ( who pilots a different vehicle each time ) in a boss fight . After the sixth zone , the player continues directly to the Final Zone for a last encounter with Robotnik .