To activate a cheat, enter its corresponding code on the VS screen. Numbers indicate how many times Turbo, Jump and Pass buttons should be pressed. For example, 5-2-5 means:

Press TURBO 5 times. Press JUMP 2 times. Press PASS 5 times. 
Always be quarterback  -  2-2-2 LEFT Requires 2 player entry 
Always be receiver  -  2-2-2 RIGHT Requires 2 player entry 
Asphalt Field  -  3-0-1 UP 
Astroturf Field  -  3-0-3 UP 
Big football  -  0-5-0 RIGHT 
Big head mode  -  2-0-0 RIGHT 

Bonus Players  -  To activate a bonus player, go to the “Enter Name for Record Keeping” screen and enter their corresponding name and personal identification number (PIN). The phrase, “Lights out baby!” confirms correct entry.

Name PIN
Alec 1197
Alien 1111
AOB 1111
Aubrey 7777
AZPOD 4777 
Beth 7761
BILLZ 0526
Boxer 2111
Brian 1111
Brian 2221
Brian 0818
Caleb 0996
Carltn 1111
Curtis 1111
Daniel 0604
David 3333
DBN 6969
Dino 1111
Ed 3246
Eddie 3333
Forden 1111
Franz 1010 
Gaston 1111
Gene 0310
Gentil 1111
Grinch 0222
Grinch 2220
Guido 2222
Guido 6765
Gamby 8698
Japple 6660
Jason 3141
Jeff 1111
Jenifr 3333
JimK 5651
John 5158
Josh 4288
Jove 6644
Lex 7777
LT 7777
Luis 3333
MarkA 1112
Mike 3333
Mitch 4393
Monty 1836
Moose 1111
MXV 1014
Nathan 0515
Nico 4440
Paula 0425
Paulo 0517
PIRATE 1111
PunkB 2112
PunkR 1221
RAIDEN 3691
Ralph 1111
RandU 6666
Rog 8148
Root 6000
Ryan 1029
SAD 1111
Sal 0201
Shinok 8337
SHRUNK 6666
Shin 0530
SKULL 1111
SMILE 1111
THUG 1111
Todd 1122
TREX 1111
Turmel 0322
Van 1234
WHODAT 1844
ZZ 1221

City Stadium  -  5-0-1 LEFT 
Current Team Play book  -  1-0-0 UP 
Day Stadium  -  5-0-1 DOWN 
Display field goal %  -  0-0-1 DOWN 
Display punt hang-time meter  -  0-0-1 RIGHT 
Fast turbo  -  0-3-2 LEFT 

Grand Champion Tournament Override  -  If you haven't noticed, once you've defeated all 30 teams you can't use any codes. Now you can. Just enter 4-4-4 Left at the VS screen and you will get the Grand Champion Tournament Override. 

Grass Field  -  3-0-0 UP 
Hide receiver name  -  1-0-2 RIGHT 
Hyper blitzing  -  5-5-5 UP 1P game only 
Infinite turbo  -  5-1-4 UP 
Invisible receiver highlight  -  3-3-3 LEFT 
Late hits  -  0-1-0 UP 

NFL Playbooks  -  To use a team’s playbook, enter its corresponding code on the VS screen. Numbers indicate how many times Turbo, Jump and Pass buttons should be pressed. For example, 5-2-5 means:

Press TURBO 5 times. 
Press JUMP 2 times. 
Press PAS4S 5 times. 
Cheat Code
All of the Teams 1-0-0 -none-

49ers 1-5-1 LEFT

Bears 1-1-0 -none-
Bengals 1-1-2 LEFT
Bills 1-0-4 LEFT
Browns 1-1-3 LEFT
Buccaneers 1-5-4 LEFT
Broncos 1-1-5 RIGHT
Cardinals 1-0-1 LEFT
Chargers 1-4-5 LEFT
Chiefs 1-2-5 LEFT
Colts 1-2-3 UP
Cowboys 1-1-4 LEFT
Dolphins 1-3-1 LEFT
Eagles 1-3-3 LEFT
Falcons 1-0-2 LEFT
Giants 1-3-5 LEFT
Jaguars 1-2-4 LEFT
Jets 1-4-1 LEFT
Lions 1-1-1 LEFT
Packers 1-2-2 LEFT
Panthers 1-0-5 LEFT
Patriots 1-4-3 LEFT
Raiders 1-4-2 LEFT
Rams 1-5-3 LEFT
Ravens 1-0-3 LEFT
Saints 1-3-4 LEFT
Seahawks 1-5-2 LEFT
Steelers 1-4-4 LEFT
Titans 1-5-5 LEFT
Vikings 1-3-2 LEFT
Night Stadium  -  5-0-2 DOWN 
No first downs  -  2-1-0 UP 
No fumbles  -  4-3-2 DOWN 
No interceptions  -  3-4-4 UP 
No out-of-bounds  -  2-1-1 LEFT 
No punting  -  1-5-1 UP 
Old Day Stadium  -  5-0-1 UP 
Old Night Stadium  -  5-0-2 UP 
Old Snow Stadium  -  5-0-3 UP 
Power-up Blockers  -  3-1-2 LEFT 
Power-up Defense  -  4-2-1 UP 
Power-up Offense  -  3-2-1 UP 
Power-up Teammates  -  2-3-3 UP 

Red, White and Blue Ball  -  At the Vs screen press turbo 3 times circle 2 times and X 3 times and you will get the red, white and blue ball. 

Roman Stadium  -  5-0-3 LEFT 
Single Player Big head mode  -  2-0-0 RIGHT 
Single Player Headless mode  -  3-2-1 LEFT 
Single Player Huge head mode  -  0-4-0 UP 
Single Player Invisible mode  -  4-3-3 UP 
Smarter CPU opponent  -  3-1-4 DOWN 1P game only 
Snow Field  -  3-0-4 UP 
Snow Stadium  -  5-0-3 DOWN 
Stadium OFF  -  5-0-0 LEFT 
Super blitzing  -  0-4-5 UP 
Super field goals  -  1-2-3 LEFT 
Super passes  -  2-5-0 LEFT 
Time (night game)  -  0-2-2 RIGHT 
Tournament mode  -  1-1-1 DOWN 2P game only 
Turbo mode  -  0-3-2 LEFT 
Weather (clear)  -  2-1-1 LEFT 
Weather (fog)  -  0-3-0 DOWN 
Weather (rain)  -  5-5-5 RIGHT 
Weather (snow)  -  5-2-5 DOWN 
Weather (thick fog)  -  0-4-1 DOWN 
Whole team big head mode  -  2-0-3 RIGHT 
Whole team big player mode  -  1-4-1 RIGHT 
Whole team tiny player mode  -  3-1-0 RIGHT