UFC Undisputed 2010 improves upon its predecessor in certain areas but weakens in other areas.
-The cage finally plays a role in the fight
-Fighters look very lifelike
-Fighters now have the ability to sway
-New fighting styles introduced
-Some fighters can switch between orthodox and southpaw stances
-Can posture up to finish the fight from any position
-After catching a leg kick, players can choose to take the opponent down or immediately attack
-Some noticebale improvements to career mode (more story driven, more options to customize created fighter's appearance, created fighter can pick and choose which moves he wants, can switch between weight classes)
-Can now transition in the clinch
-More ground positions and submissions
Cons:
-The tutorial does a very poor job of explaining any advanced concepts
-There is no way of knowing when a transition in the clinch will be successful
-In the ground game, the fighter on top can repeatedly throw punches, knees, elbows while receiving no penalty to his ability to reverse transition (this is a step down from 09)
-As explained above, reversals are easily abused
-A fighter that shoots in for a takedown and takes an uppercut to the face during the shoot does not receive any penalty to his takedown offence (another step down from 09)
-Some moves in the game are basically exploits (ex: Machida's unstoppable takedown and the Omaplata as an unstoppable sweep)
-The ref stands up the fighters too early during ground game
-When the ref stands up the fighters, they do not return to the centre of the octagon
-The decision to leave the "shine system" in the game and even force it into takedown offence and defense is foolish
-There are nearly no flash KOs
-Some very strong strikes that connect don't seem to have any impact (mainly knees)
-Although infrequent, illegal blows do exist and are not called
***The online component of the game is broken and the UFC Undisputed forums are littered with complaints about it (hard to find a game and games are usually very laggy)***
-The career mode is still very shallow, can only perform one activity per week, the computer is not cooperative when you need to perform a certain task at camps (ex: Say you need to perform a defensive ground reversal but the computer wants to stand strike instead of take you down)
Overall, it seems the developers listened to feedback from the last game that they could easily implement in the 2010 version. As for the more complex problems...hopefully they'll solve them for the UFC Undisputed 2011.