Prince of Persia: The Two Thrones

Unlock secret sword:
Pause the game play and press the following buttons on your controller:
Up, Down, Up, Down, Left, Right, Left, Right, Yellow, Blue, Yellow, Blue

Unlock Baby Rattle of Death Weapon:
Pause the game play and press the following buttons on your controller:
Left, Left, Right, Right, X, Y, Y, X, Up, Down

Ulock Telephone of Sorrow
Pause the game and press the following buttons on your controller:
Right Left Right Left Down Down Up Up X Y X X Y Y

Unlock Chainsaw
Pause the game play and press the following buttons on your controller:
Down, Down, Up, Up, Right, Left, Right, Left, Y, X, Y, X

Unlock Swordfish Weapon
Pause the game play and press the following buttons on your controller:
Up, Down, Up, Down, Left, Right, Left, Right, Y, X, Y and X

Unlock Sand Gate rewards:
Fourth Sand Tank - Deactivate 1 Sand Gate.
100 Sand Credits - Deactivate 2 Sand Gates.
Eye of the Storm Power - Deactivate 3 Sand Gates.
Fifth Sand Tank - Deactivate 4 Sand Gates.
150 Sand Credits - Deactivate 5 Sand Gates.
Winds of Sand Attack - Deactivate 6 Sand Gates.
Sixth Sand Tank - Deactivate 7 Sand Gates.
200 Sand Credits - Deactivate 8 Sand Gates.
Sand Storm Attack - Deactivate 9 Sand Gates.

Unlock Video gallery:
Finish the game.

Different endings
To fight with the Dark Prince instead of Vizier at the ending:
Get all of the life upgrades.