Fight as Akuma/Gouki
Highlight Ryu on the character selection screen and press Left.
Fight as Dan
Highlight Ken on the character selection screen and press Right.
Quick rematch
Hold L1 + L2 + R1 + R2 + Select + Start at the end of a match.
Alternate costumes
Press Kick + Special at the character selection screen.
Alternate Chun-Li taunt
Select Chun-Li and fight Felicia. Instead of having her "Gomen Nasai!" taunt, she will wave a cat toy.