The first film in the series not to be directed by Eli Roth. Roth has a philosophy that no film series should go beyond two installments, so he most likely passed on the opportunity.
Internal casino shots were filmed at the Greektown Casino in Detroit, Michigan (as evident by the Greektown logo shown on the TV monitors during the casino sequences). The Detroit Greektown Casino is the only Native American owned and operated casino located in the heart of a large populated metropolis in North America.
There were meant to be many viral marketing tools attached to the film including a collection of QR codes that would, if scanned, give exclusive content. You can see one at 1:9:26. Because of the film's reception from test audiences, the marketing campaign was dropped, and if you scan the code now the result would just show up as "top left 8."