Play as Gourki
At the Title screen press Up Up Down Down Left Right Left Right B A.
Play as Reiji
At the Title screen press A B Right Left Right Left Down Down Up Up.
Hold L before selecting your character and press Left or Right on the DPad. Then keep holding L when you select your character.
Beat Tag Team Mode on Very Easy with only one character in under 21 minutes. Don't let anyone join you.
When you get knocked down keep pressing one of the CButtons.