To fight against Shin Akuma, you must play a single-player game, uninterrupted by a human opponent. And in your quest to the end-boss you should be undefeated, with at least 3 "Perfects" under your belt.
Note: If you are using controller port 1, then your character should be a "punch" color; If controller port 2, then your character should be a "kick" color. Also, you must set guard to "manual".
To play as the "Classsic" Chun Li � the character in SF: Super Turbo Edition � highlight Chun Li, hold Start and press any button to select her.
To play in Australia, select VS mode. Then, at the Stage Select screen, highlight Sagat's stage, hold Start and press A, B, X, or Y.