Sonic and the Black Knight Cheats - Wii
Successfully complete "Knight's Passage" to unlock Lancelot, Gawain, and Percival as playable characters in Adventure mode or complete the indicated tasks to unlock the corresponding character in multi-player Battle mode:
Amy Rose - Defeat the final Boss.
Blaze - Defeat Lady Percival.
King Arthur - Collect all five of "King Arthur's Legends".
Knuckles - Defeat Sir Gawain.
Shadow - Defeat Sir Lancelot.
Silver - Complete the "Lancelot Returns" mission in the Deep Woods.
Tails - Finish the first Castle Camelot mission.
"Seven Rings In Hand" (Crush 40 version) song
Collect all seven World Rings in the Legacy levels to unlock the song at the "Gallery" menu.