Enter the following codes (some of them are case-sensitive) while playing or at the indicated screen:

Unlock AFC North All-Stars - NAOFRCTH (team selection screen)
Unlock AFC South All-Stars - SAOFUCTH (team selection screen)
Unlock AFC West All-Stars - WAEFSCT (team selection screen)
Unlock AFC East All-Stars - EAASFSCT (team selection screen)
Unlock NFC South All-Stars - SNOFUCTH (team selection screen)
Unlock NFC West All-Stars - ENASFSCT (team selection screen)
Unlock NFC East All-Stars - NNOFRCTH (team selection screen)
Unlock EA Field - EAField
Unlock Team Reebok - Reebok
No Fumble Mode - Gluehands
Always Fumble - GreasedPig
Ants Mode - RuinedPicnic
All Chains Mode - Trick3dOut
Maximum Catch - MagnetHands
First Downs Removed - NoChains
10 Yard First Downs - FirstFirst
X Gamebreaker - llxGBCraZ
10X Gamebreaker - XxGBCraZ
Max Speed - GottaBDShoes
Max Tackle - BlastTackle
Weak Jumping - CementShoes
Unlimited Turbo - NozBoost
Big Players - BIGSmash
Tiny Players - Shrunken
Random Size - SighsMatters
Big Ball - BIGPig

The easiest way to get NFL players is to do the wall dives first. If you do a wall catch at the start of the game you will not be able to beat a team in a game to 24.

When doing NFL Challenge mode, go to the Sportsplex field (the baseball field) and go all the way down to the last challenge. It should say "Sack the QB three times in this play". You can get either a Gold, Silver or Bronze. After you complete the challenge, it should say: "You won of development points", and have the choice to exit or retry the challenge. Choose "Retry Challenge". Keep doing this for however many times desired. When you go back to the main NFL Challenge menu, you will see that all the times you won the challenge, you kept the development points you won. If you did this a lot, you will have a large number of development points to spend on your player.

First, play Jump Ball Battle a lot to get some practice at being able to jump at the correct time. Then, on a real game, when the QB lofts the ball up, use the skills you acquired from Jump Ball Battle to get the easy interception.

In NFL Challenge mode, make a good QB and WR. You will be able to go all the way down the list and select "NFL Challenge". Do the NFL Challenge to unlock an NFL player. Do this until it shows that it is locked (you can fit fourteen NFL players. After it is locked, you should get an invitation to the tournament in downtown. Win the tournament and the NFL Legends. After you do that, choose an NFL Legend and NFL Challenge is now completed.

When you create the new team, make a QB with good speed and passing. Also, make two receivers that are good in terms of catching and speed and jumping. Then, go to the challenge modes. Go down to player challenges. First, play against the Ravens and acquire Ray Lewis. Then, go to the Broncos and get Champ Bailey. Then, go to the Giants and get Tiki Barber (or any other good RB). With the rest of the days, do the challenges and get your created player up better.

Go to NFL Challenge, then go down to "Player Challenge". Choose Jamal Lewis as a RB. Choose Ray Lewis as a LB. Choose Mike Vike as a QB. Choose Randy Moss as a WR. Choose T.O as another WR.

When on defense in the locking position with another player, you may be prompted to tap [A]. Hold [L] and tap [A]. This will cause you to take the ball from his hands and get a few yards.

To get 25,000 credits, have a saved game from an EA game such as Need For Speed Underground 2, SSX 3, Madden NFL 2005, the original NFL Street, NCAA Football 2005, GoldenEye: Rogue Agent, NBA Live 2005, and NBA Street Volume 2.

Win Own The City mode to get the option to export your player to Madden NFL 2006 and to your NFL Challenge team.

Press [L] + [B] by a wall and your player will run on it.

Beat the five tutorials to unlock Team Xzibit Mode.

Hit every hot spot in every level to in quick game to unlock the legends.

Beat the NFL Legends in Own the City mode to unlock them.
Beat the NFL Gauntlet to unlock Gridiron Park.

Go to The Alley and get a GameBreaker 2. Do a wall run with the GameBreaker 2. If done correctly, you will wall run 10 feet over a hotspot.