In this zone Sonic must battle against 2 bosses, a silver Sonic robot and Mecha-Robotnik (a giant armored battle suit). There are no rings available and Sonic is alone without Tails for help.
After defeating the bosses Sonic will run out of the exploding Death Egg and skydive back down, and is caught by Tails' plane (unless you have managed to collect all the Chaos Emeralds; in that case Super Sonic flies alongside the plane).
