Midway just confirmed that there will be a playable demo of John Woo Presents: Stranglehold. The demo will be released sometime at the end of this month on Xbox Live Marketplace. Midway did not mention a demo release for Playstation Network or PC.
The demo will feature one singleplayer mission, of some of the earlier missions in Stranglehold. The full version of Stranglehold will be in stores sometime in August on Xbox 360, Playstation 3 and PC.