Costumes - Enter this code in the cheat codes option.

Password Effect

KellyKG12R Kelly Kelly second outfit.
DXCostume69K2 Unlocks HHH and HBK's DX attires.

Unlockable Arenas

Complete Hall of fame Task in order to gain Points to unlock each arena.

December to Dismember Arena Get 8 points in Hall of Fame Mode
ECW One Night Stand Arena Get 7 points in Hall of Fame Mode
New Year's Revolution Arena Get 9 points in Hall of Fame Mode
No Way Out Arena Get 5 points in Hall of Fame Mode
Summerslam arena Get 10 points in hall of fame mode.
Vengeance Arena Get 6 points in Hall of Fame Mode
Wrestlemania 23 Arena Get 12 points in Hall of Fame mode

Unlockable Characters

Go to 24/7 mode and access the WWE shop

Bald Mr. McMahon Purchase Mr.McMahon.
Bret Hart Defeat Bret Hart in the Hall of Fame direct challenge mode, then you can buy him in the WWE Shop for $210,000
Mick Foley Defeat Mick Foley in the Hall of Fame direct challenge mode, then you can buy him in the WWE shop for $210,000
Mr. McMahon Win a world title match at Wrestlemania during GM Mode.
Stone Cold Steve Austin In the Hall of Fame, select Stone Cold. Defeat him in a Submission Match using Bret Hart, then you can buy him in the WWE ship for $210,000
Terry Funk Defeat Tommy Dreamer, Sabu, and Sandman in an ECW Extreme Rules 4-way mmatch using an superstar on "Legend" Difficulty. In WWE shop for $210,000
The Rock Defeat The Rock as Stone Cold in "Legend" Difficulty, then you can buy him in the WWE shop for $210,000