Two-Player Practice Mode:
You need two controllers for this (duh). Make sure they are plugged 
into the first two ports when you switch on. At the main menu, move 
the joystick to Practice mode. Now press A and hold it on both 
controllers, simultaneously. 

If you performed the code correctly, when you choose a team, 
both player selectors will appear in the left-hand column.

Adjustable Players:
At the options screen, either during the game or at start-up, press 
and hold one of the C buttons and press R. This brings up 16 zeros 
at the bottom of the screen. Use the inputs below to alter the players. 

Head Scale:
Bottom C+R at the options screen 

Body Scale:
Left C+R at options screen 

Y Scale:
Top C+R at options screen 

Bonus Teams:
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 this right , a "1" should 
appear on the tenth spot from the left. This will give you extra teams: 
Williams (I think it is the best), Canada, USA, and the 99ERS. 

Trades:
Upon starting the game, go to Setup, then Options. Hold L down and 
push DDUUDDRRD (on the C-pad) then go to the Records, and then 
access Team Stats. Now press the C button up 10 times and a special 
Modify Teams menu appears. 

Skip using the analog joystick. Use the D pad to choose two teams, and 
then press A. By pressing A, you can alternate the teams on the left, 
and by pressing B, you can alternate the teams on the right. Once both 
names are highlighted, press A to trade. Press Start when you're finished.

Like we said in the Super Teams Code, you can't play a full season with 
the super teams, but you can trade the super team players to regular 
seasonal teams (for season playing using this technique.

Non-stop Fighting:
This is cool if you just want to fight all the time, because, in fact, you'll be 
fighting every second with this code on. Good to surprise a friend, maybe. 

During a game, go to the Options menu and highlight fighting. Then hold L 
(left) and press these C buttons in this order: RLLRBTTBLRRLRL. R=right, 
L=left, B=bottom, T=top. 

If you've entered it correctly, a string of zeroes will appear on the bottom 
of the screen.

Ads at Options: To get ads at any Options screen, press "Z" for an advertisement that will 
scroll across the bottom of the screen. 

Disappearing Players:
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.