All-star team - Turn the salary cap off, find a player you want (for example, Calvin Johnson). Select him, go to "Edit Player", and change him to a QB. His rating will drop to 12. Press Start, and choose to keep the player without saving. Trade your lowest rated WR for him. The trade will be accepted. Then, go back in and change him back to a WR. You will now have Calvin Johnson without losing an important player. Repeat this process to create an all-star team.

Secret messages - Throw 500 career touchdowns to get the "Congratulations from the Madden NFL 10 team! Brett who?" message.

Score approximately 112 points in Franchise mode. The message will appear at the bottom of the screen.

Trophies - Successfully complete one of the following tasks to get a trophy:

Sprint 2 Minute Drill (Bronze): Win after being behind in the final 2 minutes of a game. 5 min qtrs, All Pro (no co-op).
Fight for the Fumble (Bronze): Win possession of the ball after a fumble pile-up. 5 min qtrs, All Pro (no co-op).
Frozen Tundra (Bronze): Win at Lambeau Field in freezing weather. 5 min qtrs, All Pro (no co-op).
The Gang's All Here (Bronze): Trigger a gang tackle with 7+ players. 5 min qtrs, All Pro (no co-op).
All Day No Way (Silver): Record 3 tackles for a loss on Adrian Peterson. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
Buzzkill (Silver): Intercept a pass intended for Randy Moss. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
From Me To You (Silver): Complete a pass for a TD with your partner in an Online Co-op game. 5 min qtrs, All Pro.
Go Back to Basketball (Silver): Tackle Antonio Gates inside the 5 yard line. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
Go Bag Some Groceries (Silver): Force Kurt Warner to fumble on a sack. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
Have to Be This Tall to Ride (Silver): Stiff arm or juke Bob Sanders. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
Hey Buddy! (Silver): Complete a lateral with your partner in an Online Co-Op game. 5 min qtrs, All Pro.
Larry Stickyfingers (Silver): Get 10 user catches (no drops) with Larry Fitzgerald. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
Laser Arm? (Silver): Intercept Peyton Manning 3 times. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
Mr. Not-So-Perfect (Silver): Intercept a Tom Brady pass. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
Nothing Without the Dark Visor (Silver): Force a LaDanian Tomlinson fumble. 5 min qtrs, All Pro (no Pro Bowl, no co-op).
Look what I found! (Gold): Win a fumble pile-up in the end zone for a TD. 5 min qtrs, All Pro (no co-op).
Nano (Gold): Sack the QB before he can hand the ball off. 5 min qtrs, All Pro (no co-op).
Pocket Monster (Gold): Stay in the pocket for at least 10 seconds. 5 min qtrs, All Pro (no co-op).
Super Bowl MVP-like (Gold): Catch a TD to take the lead with under 30 seconds left. 5 min qtrs, All Pro (no co-op).
Why Can't We Be Friends? (Gold): Complete an online Co-Op game. 5 min qtrs, All Pro.
Wounded Duck (Gold): Complete a pass to an unintended receiver. 5 min qtrs, All Pro (no co-op).
Madden NFL 10 Master (Platinum): Congratulations on earning every Madden NFL 10 trophy!

Additionally, there are three secret trophies:

Well played. Really. (Bronze): Throw the ball away on 4th down. 5 min qtrs, All Pro (no co-op).
Mature Newbie (Bronze): Create a player or Superstar at the oldest possible age.
Safety Inspection Required (Bronze): Create a team from Springfield.

The following trophies require the "AFL Legacy Pack" bonus downloadable content:

AFL Goes Online (Silver): Play online wearing AFL jerseys. 5 min qtrs, All Pro (no co-op).
AFL Invades Franchise Mode (Silver): Win an offline franchise AFL Legacy game with AFL presentation turned ON.
Blast From The Past (Silver): Win an AFL-themed Madden Moment with AFL presentation turned ON.
Orange Sherbet Anyone? (Silver): Win an exhibition game with AFL presentation turned ON. 5 min qtrs, All Pro (no co-op).