UFC Undisputed 2009 was one of the big gaming success stories of last year, selling over 3.5 million copies.

The new 2010 edition, which featured more fighters, more moves, a revamped control system and an enhanced career mode was well received in the gaming press, but Gamasutra reports that according to a market analyst its selling, “slower than anticipated.”

The analyst also points to Amazon’s decision to drop the price of the game from $59 to $39 just a week after it’s launch as evidence that the title isn’t meeting it’s expected targets.

What remains unclear is exactly why the game is not selling, as the game has been well received and the UFC has been performing well in recent months with a series of high-profile events.

The analyst GamaSutra spoke to suggests that other high-profile titles like Read Dead Redemption and could be, “adding some competitive pressure.”

That could well be true, but there’s other factors to consider. For instance I think there was a ‘novelty’ factor to last years edition. It was different from a lot of other fighting games out at the time, and that would have helped draw in gamers who aren’t necessarily even fans of the sport.

Without being devout fans of the sport it’s questionable whether they would be wiling to shell out more money for an updated version of the game a year later though. There’s also some suggestion that as the game is becoming even more complicated and technical, that it’s alienating those who don’t have a full appreciation for the sport.

Meanwhile for the MMA fan there is the lure of EA Sports MMA title, a new arrival to the video game market which will come out later this year. If you already have Undisputed 2009, then the temptation may be to wait it out and opt for a completely new game instead.

There’s also the fact that some fans and reviewers have noted that flaws in the 2009 game still exist in the updated version, such as the repetitive career mode, flawed online play, and the submission system remains unsatisfying to many.

Whatever the reason we can only hope that this is a temporary hitch and that the game will perform well as the success of a product like this is good for the sport of MMA as a whole.