Once you beat the game the classic Prince of Persia game will be available. Here are some passwords for that game:
LRARUC Battle with Jafar
MZFYSC Level 10
BRAYQC Level 11
UUGTPC Level 12
KIEJSC Level 2
VNNNPC Level 3
IYVPTC Level 4
RWSWWC Level 5
GONWUC Level 6
DEFNUC Level 7
SVZMSC Level 8
DBJRPC Level 9
Start a New Game and stay on the balcony. Press in the left analog stick, then quickly press A,X,Y,B,Y,A,X,B.
You'll enter the fist level in the original Prince of Persia in 3D.
Around 33% of the way into the game, you will receive a new sword. Continue on until you break a wall and the Prince says, ''It's said they built this palace on the ruins of another...'' Once you cross the next room, you will find a rotatable switch. Directly behind this switch is a breakable wall, although it doesn't appear to be one. If you hit it three times, you will find another room and you will receive a message informing you that Prince of Persia 2 is now unlocked.
You can also rotate that switch until it points to the new room and it will open a gate that allows you to play Prince of Persia 2 right there without having to exit back to the Extra Features screen.
Beat the game and Prince of Persia 1 will be playable in the extra options menu.