Play as Way of the Samurai 1 and 2:
Successfully complete all levels (including the extra levels) under the super hard difficulty setting.

Other bonus characters:
Find the wanted posters in the following levels to unlock the corresponding character.

Faceless
Hard level 8 (Saloon): Found over the chandelier

Donna
Hard level 11 (Cactus Gulch): Get to a position where the train station is behind you. Look on the terrace of the building to the left and diagonal from your location.

Killer
Hard extra level 2 (Coal Mine): Above the coal mine entrance.

Nathan
Hard level 9 (Coal mine): From the starting location, search the building directly in front, and beyond the slippery ground.

Jean
Hard level 12 (Wilderness): Found in the air next to the bridge.

Rando
Hard level 15 (Fort): Search the back of the right side of the fort.

Goldberg (normal)
Hard level 16 (Goldberg Residence): Look behind the back stairs inside Goldberg's room.

Goldberg (battle)
Easy extra level 1 (Fort): Found diagonally above the statue.

Harvey
Hard extra level 4 (Coal Mine): Look behind the bridge.

General
Hard level 7 (Cactus Gulch): Search inside the small room along the tracks.

Lanky
Hard level 14 (Wilderness): Look around the entrance to the level.

Oaf
Hard level 2 (Saloon): Search down by the stairs.

Ripper
Hard level 1 (Cactus Gulch): Found above the general store next to the saloon.

Eve
Hard level 3 (Cactus Gulch): Hidden in the back of the small path next to the train station,

Bart
Hard level 6 (Fort): Found in an opening by the entrance to the courtyard.

Vile
Hard level 4 (Ghost Town): From your starting position, look behind the road blocking sign in front of you.

Little Baby
Hard level 5 (Goldberg Residence): Found behind a door.

Faceless (type 2)
Hard level 13 (Saloon): Look on the pipe next to the stage.

Claudia
Hard extra level 4 (Coal Mine): Go past the bridge and enter the room with a crane. It is on the wall to the right.

Anne
Hard level 10 (Ghost Town): Found in mid-air in the cemetery.

Joey
Hard level 9 (Coal Mine): Go past the bridge and look above the dead end to the right.

Ralph
Hard level 16 (Goldberg Residence): On the first floor, search the pipe on the back left.

Urchin
Normal extra level 5 (Wilderness): Look at the top of the hill.

Sweetheart
Normal level 16 (Wilderness): Look in the dining room, behind the screen.

Brat
Hard level 10 (Ghost Town): Search inside the bathroom.