Dhalsim: While in the air press Forward, Forward, Up, Up, Back, Up, Back.
Sakura: press Low Kick, Low Kick, Back, Low Punch, High Punch.
Skullomania: press Forward, Forward+Down, Down, Back+Down, Back, Back+Up, Up, Forward+Up and any Punch.
Keep passing tests in practice mode and you'll eventually unlock some hidden characters such as Evil Ryu, Shin Bison and even Shin Garuda and more.
Press Select, Up, Up, Right, Up, Right, Up and Select at practice mode. Enter the practice mode, and there you will see your new bonus game.
Go to the Mode Select screen and highlight Practice. Then press Select, UP, RIGHT, DOWN, RIGHT, Select.