Unlock Eddie Guerrero
To Unlock Eddie Guerrero you have to defeat Brock Lesnar at the No Way Out arena on the Legend difficulty to unlock Eddie Guerrero.
Unlock Retro Undertaker
Defeat the Streak with Diesel or Bundy at WrestleMania 11/12 to unlock Retro Undertaker. Alternately, defeat the Streak with Kane at WrestleMania 14.
Defeat the Streak with Batista at WrestleMania 23 to unlock Undertaker. Alternately, defeat the Streak with HBK at WrestleMania 26.