Cheat mode:
Enter the Easter Egg menu and enter one of the following codes to activate the corresponding feature:

Result - Code:

All players' last names are - BOBO BOBO
Big players - BUNYON
Speed juiced - COFFEE_BREAK
CPU hides pass coverage - CON_MAN
CPU players are faster - CPU_SCORES
Large football - BIG_BALLS
Louder noises - BIG_HITS
No penalties - BLINDERS
CPU offensive line has super strength and speed - CPU_STUFFS
View credits - CREDITS
Running back is juiced - DAVIS
Zero stamina and more fatigue injuries - EGG_HEAD
All players have European last names - EURO_LEAGUE
All players are equal - EVEN_TEAMS
Tiny players - FLEA_CIRCUS
Bonus difficulty level - GD_CHALLENGE
Red redzones, checkered touchdown area, invisible field goals - GRUDGE_MATCH
More hamstring injuries - HAMSTRUNG
Punts hang in the air longer - HANGTIME
All players have last name from credits SPORTS
Ball carrier has speed bursts - ROCKET_MAN
CPU knows your play - MIND_READER
CPU makes big plays - PRIME_TIME
CPU player celebrates in the open field - HOT_SHOT
Flat players - PLAYING_CARDS or FLAT_LAND
Great hands for receivers - STICKEM
Invisible players - INVISIBLE
Juiced endurance - STAMINA
Longer field goals - STEEL_LEG
Players have red string attached to head - PUPPETS
Players named after basketball players - HOOPS
Players named after Presidents - PRESIDENTS
Players named after programmers - RED_ZONE
Quick fatigue - WEAK
Scrambled frame rate - ITS_IN_THE_FPS
See cheerleaders after a game - SLIDESHOW
Small, fast players - POP_WARNER
Super stiff arm - POLE_AXE
Swim move juiced - SWIMMERS
Televisions in players' stomachs - TELE_TUMMY

Extra teams:
Press Circle at the team selection screen to access various Superbowl and All-Star teams.