Acquire Raiden: Finish hard mode in infinity mission.
Acquire Naked Snake: Finish easy mode in infinity mission.
Acquire Roy Cambell: Finish extreme in infinity mission.
Acquire Old Snake: Finish Medium mode in infinity mission.
Acquire Boss Rush Mode: Save the game on your PSP memory stick for the original Metal Gear Solid: Portable Ops. Begin a fresh game on Portable Ops Plus with the original save data to acquire this special mode.
