Complete the indicated task to unlock the corresponding costume.

Apron Dress: Complete the game under the Easy difficulty.
Business Suit: Complete the game. Note: The costume is in the left hand locker room in the CTI Building.
China Dress: Complete the game under the Normal difficulty.
Knight Armor: Complete the game under the Deadly difficulty.
Lightning Custom: Complete the game and have at least seven stamps on the Square-Enix Member site. Alternately, complete the game nine times.
OD Suit: Complete the game and have at least one stamp on the Square-Enix Member site.
Santa Soldier: Complete the game. Note: The costume is found by going down the stairs to the lockers in Maeda's Base, and searching the one on the left.
Swim Wear: Complete the game under the Hard difficulty.
Titanium Bunny: Complete the game under the Genocide difficulty.