The Moon Zone (ザ・ムーンゾーン,Za Mūnzōn?) is the extra Zone in Sonic Advance. It can be accessed if the player has collected all of the Chaos Emeralds and finished the game with all the characters. It takes place at the end of Sonic's story after completing the X-Zone.
After defeating the mech, Sonic will disappear for a few days. Then, while Tails is flying the Tornado, he spots a streaking yellow light, which turns out to be Super Sonic. He will give a smile and the credits will roll.
The main and only boss of The Moon Zone is the Super Egg Robot. This boss is somewhat effortless, jump and dash when his head is exposed. Sometimes, Eggman will fire a pod: if it catches Sonic, he'll stay inside the pod until he manages to break free. If charged at, the pod will release Rings. This is essential to collect Rings as the ring counter will slowly deplete and if Super Sonic has no Rings left, he will lose a life. Eggman will also fire a laser which causes the ground to burst out energy columns that will knock Super Sonic back a little but it can be avoided while jumping. At times, the arms will vibrate, which will cause some fragments to fly into the air.
The background of this zone is similar to the Moon Rise image photographed during the Apollo Missions (AS11-44-6553).