소닉 어드밴스

Tails as partner:
Highlight Sonic at the character selection screen and press Up. Next, highlight Tails and press Down. Then, highlight Knuckles and press L. Finally, highlight Amy and press R. Highlight Sonic and press A to select him. If done correctly Tails should be behind Sonic and follow him along the course you select. However, you cannot control Tails. Instead he will make what you do and grab rings for you. 

Alternately, Sonic should already be highlighted at the character selection screen. Press Up, Right, Down, Right, L, Right, R, Right, A. If done correctly, Sonic will be highlighted again. Select him, and a ring sound will confirm correct code entry. Tails will follow you through the game but cannot be controlled. Repeatedly press A to make Tails fly. Note: Tails cannot pick you up while he is flying.

Note: Tails sometimes useful for collecting rings that you do not pick up, re-collecting stray rings if you are hit, and can also do damage to enemies when spinning. This is especially useful when fighting against Eggman.

Moon Zone:

Collect all seven Emeralds for all characters. Successfully complete the game as Sonic to unlock the Moon Zone.

출처 : http://www.gamewinners.com/game_boy_advance/SonicTheHedgehogAdvance.htm