Street Fighter Alpha 2

Unlock Australia Stage
Choose the VS mode. Go to the stage selection menu and highlight Sagat.
Hold Start at least 5 seconds and hit any button.

Unlock Thailand Stage
Choose the VS mode. Go to the stage selection menu and highlight M. Bison.
Hold Start at least 5 seconds and hit any button.

Unlock Chun Li in Street Fighter 2 costume
Highlight Chun-Li at the fighter selection screen, hold Start,
and press A + B + X.
or
Go to the fighter selection menu, and highlight Chun Li. Hold Start
at least five seconds and hit any button.

Unlock Evil Ryu
Go to the fighter selection menu, and highlight Ryu. Press Start,
then press Right to Adon, Up to Akuma, Down to Adon, and Left to Ryu.
After hold Start and press all 3 kick or punch buttons.