Andrew Weymes of The Nightly Gamer writes: "Mixed martial arts is clearly on the rise in popular culture. What was once thought of as barbaric when compared to other combat sports such as boxing is now well respected and held in the same regard for the most part. Fighters like Chuck Liddell, Anderson Silva, BJ Penn and George St-Pierre are some of the most renown and respected professional fighters in the world. It's no surprise that THQ is jumping on the popularity of the sport and releasing a UFC fighting game in the same vein as their extremely popular WWE Smackdown series. The demo for UFC 2009 Undisputed hit the Xbox Live market place the other day and while the production values are certainly high, the fighting itself is not the best. Much like the way that the Smackdown series has much more appeal to fans of the WWE, UFC 2009 Undisputed likely won't appeal to those that haven't already bought into the MMA craze."