Wait for the words "Press Start" to flash on the Title screen. Now press C-Up, C-Up, C-Down, C-Down, C-Left, C-Right, C-Left, C-Right, B, A. Then hold the Z button and press Start. You'll hear the announcer shout to confirm the code.
At the "Press Start" screen press Up, C-Up, Up, C-Up, Down, C-Down, Down, C-Down, Left, C-Left, Right, C-Right, Left, C-Left, Right, C-Right, B, A, then hold Z and press Start.
At 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. Be sure to use the D-Pad to enter directions.
Complete the International Cup on Level 4 or higher. Once you have viewed the end sequence go to create player. At the "head select" screen press the Left Shoulder button. This will take you to page 11 and a selection of strangely unusual heads.
Different Tricks - Press and hold C-Left. The player will start doing tricks, such as rolling the ball up on his foot and juggling it around on his knee and feet and head. Different players have different tricks.
Maradona Spin - While playing, get the ball on offense. Using any player, push the Dash button to perform a dash. During the dash, rotate the Analog 360 degrees to execute a Maradona spin.
Diving - When your player gets tackled and doesn't fall, immediately press a direction on the D-Pad + the one-two pass button, the through pass button, the shoot button and the cross button simultaneously.
Complete the International Cup on Level 4 or higher to get clowns faces and aliens faces as choices in create a player.