Unlock Secret Costumes.
A screen will show you the Boutique Key after the credits. This key unlocks the door to the Boutique in Uptown. Inside the Boutique, you'll find new costumes for Jill. Based on your ranking, you'll get numerous costumes,
E Rank: 1 costume
D Rank: 2 costumes
This goes on until you have 5 costumes.

The Mercenaries:
Operation Mad Jackal Bonus Game.
Beat the game. Then reload that saved game to play the Bonus Game.