During the face-off before actual gameplay, pause and go to Replay. Make a player flash by pressing the L or R buttons, each time you press another player will be highlighted. While a player is flashing press the "Z" button. He will disappear, and if you want you can make all of the players disappear.
At the Options screen hold L and press C-Right, C-Left, C-Left, C-Right, C-Left, C-Left, C-Right, C-Left, C-Left. If you did the trick correctly a "1" should appear on the 10th spot from the left. This will give you the extra teams: Williams, Canada, USA, and Northeast
At the Options screen press C-Down + R, C-Left + R or C-Up + R. A screen will appear where you can modify a 16-bit register. You can only alter the first 6 bits, but that's enough to change the game's appearance. To alter the bits, use these controls: C-Down + R: changes head size C-Left + R: changes body size C-Up + R: changes height Here are a few examples: 100000: Stocky Players. 010000: Stocky Players, Big Heads. 110000: Stocky Players, Small Heads. 001000: Small Players, Small Announcer. 000100: Large Players, Large Announcer. 000010: Crunched Players, Small Announcer. 000001: Elongated Players, Large Announcer. 110110- Large Players, Small Heads, Large Announcer 010010- Crunched Players, Large Heads, Small Announcer 010101- Large Players, Large Heads, Large Announcer 010001- Elongated Players, Large Heads, Large Announcer.
Press A (20 times) at the title screen.
When you get to the main menu, move the joystick onto Practice mode and A on one controller. Then at the same time, hold A on the second controller. It will allow you to have two-players in the practice mode.
At the Options screen, hold L and press Right C, Left C, Left C, Right C, Down C, Up C, Up C, Down C, Left C, Right C, Right C, Left C, Right C, Left C