Amy's Treasure Island, also referred to as just Treasure Island, is a mini-game featured in Sonic Battle, exclusively for the game's multiplayer function. It is unlocked after clearing Amy's episode in Story Mode. Here, anyone from two to four players, each with their own Game Boy Advance system, can play together. Howeever, only one Sonic Battle Game Pak is needed to serve as the host.
Amy's Treasure Island is centered around a gameplay style reminiscent of the Treasure Hunting stages in Sonic Adventure and Sonic Adventure 2. When starting the mini game, the playable character are dropped in a flat, small and square-shaped 2.5D arena that is based on Emerald Beach's. From there, the players' objective is to seek out three Emeralds that are hidden out of sight around the arena. These Emeralds can be found by digging in the appropriate spots with a Spin Attack-based maneuver. Should the playable character dig in close proximity to an Emerald, then a white arrow will briefly point in the general direction where the Emerald can be found. However, the arrows can only point on the four cardinal direction. Once the playable character is close to the Emerald, their icon on the HUD will start to jump. Obtaining an Emerald will award the player with one point.
Amy's Treasure Island has no time limit; instead, the first player to collect three Emeralds will be declared the winner.
To move around in the arena, use and to dig, press .
List of playable characters
When beginning Amy's Treasure Island, the players are given one out of four playable characters, with the character assigned being based on the player's number. The different characters given to the players are as follows: