New Division:
At the options menu hold the L button and push the following C buttons: Right Left Left Right Left Left Right Left Left
A bunch of numbers appear and now when you pick Play Game mode you will see another division with team 'Williams the 99er's Canada and USA.'

Invisible Players:
Press start during the game and go into replay. Press L or R to make a player flash. Then press Z to make him disappear. Note:If you go over an invisible player he will reappear so be careful!

Multiplayer Practice:
To play in practice mode with more than one player, each player aside from player 1 should hold the A button at the title screen, then have Player 1 highlight "Practice" and press A. If you do this, all of the player who were holding A will get to play in practice mode together.

To have the N64 play against itself:
At the Team Select screen, highlight the team you would like to use and press C-Right 3 times. You will hear a click to tell you that it worked.

Trades:
Go to Setup, then Options. Hold down L and press the following C buttons: Down, Down, Up, Up, Down, Down, Right, Right, Down. Now go to records and access Team Stats. Press C-Up 10 times. A special modify teams option will appear.

Non-stop fighting:
During the game go to Option and highlight Fighting. Now hold L and press the following C buttons: Right, Left, Left, Right, Down, Up, Up, Down, Left, Right, Right, Left, Right, Left. You should now get into a fight every time you check.

Debug Mode:
At the Options screen press C-Down + 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.

To alter the bits, use these controls:

C-Down + R: alters bits 1 and 2 (10, 01, 11)
C-Left + R: alters bits 3 and 4 (10, 01)
C-Up + R: alters bits 5 and 6 (10, 01)

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 anouncer.
010010: Crunched Players, Small Heads, Small Announcer.
010101: Large Players, Large Heads, Large Announcer.
010001: Elongated Players, Large Heads, Large Annpuncer.

Thanks to Game Revolution readers Matt Hagel, Mike Schwarzkopf, Adam Barnhardt, Wesley Newman, Thomas Faulks, Blobson the Rat, Josh Torrenga, Errol Wilcox, Ian Beaudette and Cyrus!!