John Woo Presents Stranglehold Cheats

In the first chapter (Hong Kong Marketplace), head to the Ambushed section. After you kill everyone in the courtyard and move along the alleys, you will be forced inside a building (there's no where else to go). As soon as you enter, there should be a door you can break. Break it and go along the corridor until you reach a movie theater. On the movie screen are trailers for Wheelman and Blacksite.

John Woo Presents Stranglehold Unlockable: Increased Difficulty

To unlock a harder difficulty that is originally unavailable in the game, complete the game once through on Casual Mode.