Big Head Mode
Press C-Down(2), C-Up(2), C-Right, C-Left, C-Right, C-Left, B, A. Then, hold Z and press Start as PRESS START flashes on the screen.
Using the player creation scren, choose a name and position for a player. After highlighting any face, hold C-UP, then hold L or R and Zidane's face will be seen.
After beating the International Cup at #4 diffiulty or higher you can go to the player creation screen and find a strange set of heads by pressing L.
World Stars Team
As the phrase START flashes on the title screen Press Left, C-Left, Right, C-Right, Left, C-Left, Right, C-Right, Down, C-Down, Down, C-Down, Up, C-Up, Up, C-Up, B, A then HOLD Z and press START
When a player gets tackled but does not fall quickly hold the D-Pad in any direction and press A + B + L + R OR C-Left + C-Right + C-Up + C-Down