Banned In Singapore: Was originally banned from the country for excessive violence and blasphemy, but in 2008 after the country introduced a proper video game ratings classification system it was re-classified to M18 and released.
Blooper: During the opening stage of The Darkness II, Jackie's right leg gets torn up quite badly in a mob ambush, and one of his men must drag him away while Jackie fends of attackers with a pistol. Shortly after, the situation becomes dire enough that Jackie must unleash the Darkness to survive, and the Darkness' Healing Factor completely restores his leg, though he is missing his right shoe with the pants on that side still all torn up. In a later scene in the level, Jackie is knocked on his back and his legs flail up in front of the camera before he lands. In that shot, his pants and shoe are restored, though at no point by then would he have an opportunity to get fresh cloths.
The Angelus was originally planned to make an appearance in the first game, but was cut from the final release. It is frequently mentioned in the sequel and is revealed to be Jenny in the ending.
The sequel was supposedly planned to have a Downloadable Content as there is a main menu option for it in the final version. However, as 2K Games shifted its attention to the more successful and popular Borderlands 2, any DLC plans for the Darkness II were scrapped instead to make more content for BL2.