Part 16

G-mel Boss Fight: G-mel has several attack patterns. The first involves a beam that electrifies and paralyzes Super Sonic if touched; dash through it or avoid it. Another attack has grapplers extending and firing missiles; it's safer to charge up Eggman away from the missiles. A wide beam attack moves up and down and is easy to dash through. The final attack involves four grapplers spinning like a pinwheel; stay moving in a circle between two grapplers and collect rings. The attacks do not always occur in order, especially towards the end. G-mel requires 12 hits to defeat.

Extra Ending: After defeating the final boss, a series of scenes play out. Sonic wakes up to Tails, Cream, and Amy. Amy hugs Sonic, who seems unsure how to react. A smoking object falls from the sky in the background. Later, Sonic, Tails, Cream, and Amy stand by the Master Emerald, and Sonic departs. Knuckles arrives. Cutscenes show G-mel on a beach, discovered by Cream and Vanilla. Tails repairs G-mel, who is then seen with a flicky bird. Cream is happy. A tea party scene shows Cream hugging G-mel. The credits roll, followed by a post-credits scene where Cream chases G-mel, trips, and G-mel comforts her. They run off together, and "Sonic Advance 3 End" appears.

Unlocking Special Stages and Chaos Emeralds: To access Special Stages and earn Chaos Emeralds for the Extra Ending, follow this process for each Zone: find all 10 Chao, collect the Special Keys, locate the Special Spring, and beat the Special Stage.

Chao: There are 10 Chao per Zone, totaling 70 in the game. Finding all 10 in a Zone and defeating the Final Boss yields Special Keys. Some Chao require specific teams to obtain. Found Chao go to the Chao Playground, accessible via a spring in the Factory. The Chao list in the Chao Playground shows progress, with the Chaos Emerald appearing in the middle of the list once obtained for a Zone.

Special Keys: After finding all Chao in a Zone, Special Keys appear in the Acts. You must keep the key throughout the act without dying. Only one key can be held per act; picking up one makes others disappear. Keys can accumulate in Map areas. Once 9 keys are collected, no more appear in Acts. Key locations can be inconsistent; if a key isn't found where expected, quit and re-enter the act. The guide provides locations for keys near the beginning of levels.