Press back on or . This can be performed in midair.
Backflip
Simultaneously press up and back on or .
Knockdown Counter
After getting knocked down, press back to down-back to down on or while pressing any punch button.
Alpha Counter
After a successful block, (assuming the character is facing right) quickly press back to down-back to down on or + any punch or kick button.
*Must have at least one level filled on your Super Combo gauge.