At the versus screen enter this code by using the L, R & A buttons:


2-1-1 Left              Allow Out Of Bounds    
2-2-2 Left              Always QB (Two Players on a Team) 
2-2-2 Right             Always Receiver (Two Players on a Team) 
0-3-4 down              Arctic Station
5-4-3 Right             Armageddon Team
0-0-3 up                Auto Passing Icon
0-2-5 Left              Big Feet
2-0-3 Right             Big Head Teams
2-0-0 Right             Big Heads
3-1-0 Up                Bilders Team
4-3-2 Down              Brew Dawgs Team
0-3-3 Right             Central Park
0-2-5 up                Chimp Mode
0-3-0 down              Chrome Ball
0-3-0 Left              Classic Ball
1-2-3 Right             Clear Weather
4-0-3 Right             Crunch Mode Team
0-0-3 down              Disable Auto Passing Icon
3-3-3 Down              Extra Play for Offense
0-0-1 right             Extra Time
2-4-0 Left              Fast Passes
0-3-2 Left              Faster Running 
2-3-2 Down              Ground Fog
5-0-1 Up                Gsmers Team
1-4-5 Left              Huge Heads
2-5-3 Right             Midway Team
2-1-2 Right             More Code Entry Time
3-4-5 Up                More Fumbles
3-4-4 Down              Neo Tokyo Team
0-1-2 down              No CPU Assist (*2nd player agreement is required*) 
2-1-0 up                No First Downs (*2nd player agreement is required*)
3-2-1 Down              No Highlighting Receivers
3-5-5 Up                No Interceptions
1-4-1 Up                No Punting
5-2-3 down              No Random Fumbles (*2nd player agreement is required*)
5-5-4 Right             No Replays
3-2-5 Up                Noftle Mode
0-2-5 right             Power Loader
4-2-1 Up                Power-Up Defense
5-2-1 Up                Power-Up Linemen
4-1-2 Up                Power-Up Offense
2-5-4 Up                Rollos Team
0-2-1 right             Show More FIeld (*2nd player agreement is required*)
3-5-1 Right             Showtime Mode
3-1-4 Down              Smart CPU Teammates
0-5-4 up                Super Blitzing
1-2-3 Left              Super Field Goals
1-1-1 down              Tournament Mode (*2nd player agreement is required*)
0-3-5 up                Training Grounds
4-1-5 Up                Unlimited Turbo
5-5-5 Right             Weather: Rain
5-5-5 Left              Weather: Snow

Unlock all stadiums and two extra ones 
     While the exhibition or Season game is loading, press the following:
L button 3 
R button 1 
A Button 4 
     Then press the control stick right in that order
     Once  the  code is put in, two extra stadiums, the Training Field
and the Arctic Station will be unlocked
     On  the menu there should be all of the stadiums available in the
Stadium List

Sticky Hands & Super Intercept 
     To  unlock  the  Sticky  Hands  & Super Intercept abilities for a
created player, win 24 games in Exhibition mode.

Hidden Players 
     Enter the ID and Pin Numbers to play as secret players.

ID            PIN
BEAR          1985
CLOWN         1974
COWBOY        1996
DEER          1997
DOLPHIN       1972
EAGLE         1981
HORSE         1999
LION          1963
MADISON       1220
PATRIOT       2002
PINTO         1966
PIRATE        2001
RAM           2000
RBL-DBN       9669
ROBOTR        1973
ROBOTS        1970
TIGER         1977 
VIKING        1977
ZEMAN         1986