Bound in Blood is a first-person shooter in which the player controls one of two protagonists: Ray McCall or his brother Thomas, each of whom has a different style of gameplay.[4] Whereas in the original Call of Juarez, the player controlled alternating characters from level to level, in Bound in Blood, most levels offer the player the choice of which character to play as.[4] The character which the player does not choose is controlled by the AI for the duration of the level.[4] There are also occasional levels through which the player must play with a specific character.[5]
In many levels, there will be times when the brothers will have to directly help one another, such as Thomas helping Ray to reach a high platform, or Ray kicking down a door for Thomas.[5] Most levels are played through in the same manner, irrespective of which character is chosen, with the only difference being that of gameplay. Occasionally, however, the brothers will separate within a level (such as Ray going through a mine, and Thomas going over it), and in these cases, the level design will be different depending on which character the player is using.[6]