In Ninja Gaiden 3: Razor's Edge on the PS3 and Xbox 360, there are quite a few unlockable alternate costumes, as well as exclusive costumes from pre-order bonuses. Here are the costumes that you can unlock, and how to unlock them.
Ayane's Blossom of Miyama – Collect all 50 Golden Scarabs
Ayane's Phantom Butterfly – Purchase for 15 million Karma
Ayane's Raging God – Nine of Violet – Find all 10 Crystal Skulls
Kasumi's Brilliant Lapis – Purchase for 15 million Karma
Kasumi's Gentle Snowfall – Complete 50 different trials with Kasumi
Kasumi's Immaculate White – Complete 25 different trials with Kasumi