Had the potential to be a brilliant MMA game however one major flaw tends to destroy it
I guess i'll start by saying while this game has it's flaws, it still is relatively fun - especially if you're playing as a stand up fighter. And to that extent it is fairly realistic. But that being said let's get straight down to the pros and cons.
This is a great looking game - The fighters are modelled very realistically and when you are playing as fighters with real life counterparts they are easy enough to pick exactly who that counterpart is (forgetting the name being displayed of course haha).
The animations are extremely fluid and do give you the feeling of controlling a proper fighter - that mixed in with the complexity of the gameplay and you have a powerful mix.
For the most part the gameplay is solid - punches, kicks, knees, moving in for muay thai clinches or going for takedowns are all implemented and although they can be tricky to counter, what with the intricate right stick controls, and satisfying when landed correctly. It also brings a savage grin when you land a really solid hit and rock your opponent.
Outside the ring, the event and skill management is decent enough, although after finishing the game with your first fighter, it becomes a little more tedious rather than entertaining. But honestly that is only a minor gripe.
The sound is very strong in this game. The commentary matches the kind of techniques and strikes you pull off in real time which helps pull you in to the fight, and the sounds mapped to the actual techniques are very realistic, even when slamming your opponent into the mat.
Now for the cons...
Really there is only one major con for me in this game. Being a mixed martial arts fighter myself, i tend to be a harsh judge in terms of how the game plays out and what should / should not happen. In most cases, it is very solid and is a joy to play. But then comes submissions.
In a real fight, if you get into a strong submission position, it really doesn't matter how long the fight has been going for, there isn't much your opponent can do - they will have to tap out. Unfortunately, in UFC Undisputed submissions are (as far as i've found) fatally flawed. Let's not put a dampener on the whole game - playing through and training your skillsets into muay thai or boxing etc as stand up fighting and whatever takedown / ground game you want is fine. Holding your own on your feet is great and honestly, that's how most of the fights are finished - with KO's (talking about career mode btw). Even when it comes to moving around on the ground - going from full guard, to half guard to full mount is fair but from that point things get a little sticky.
To start off with, you do have counters for any movement your opponent does on the mats. However, the computer ai tends to full reverse you off full mount withing 10-20 seconds of you getting it - which is a right pain in the ass. But that's not the be all and end all. You can get a few KO's via ground and pound, but it's not the decider. Fact is, you can (and i have tested this) beat the living snot out of your opponent (in addition - this was with a character trained almost exclusively in Brazilian Jiu Jitsu) - rock them a number of times, then decide to take them to the ground. From there, quick transitions will land you into any place you want to continue your ground game. For this example lets talk an arm bar off full mount. There are three stages to each submission, the initial pull, the extension, and the tap out. After the previously discussed lead up to this position, you will get the to the extension (them being fatigued, beat to hell and now in extension of an arm bar) - even so there is a 99% chance they will escape the submission. It is ridiculously frustrating - especially when you consider how many fights in UFC are actually finished with submissions rather than knockouts.
Honestly, it was for that reason i stopped playing the game. It was far too frustrating when you know the realistic outcome to fights like that and to have a computer player thwart you virtually every time, no matter how physically destroyed they are.
In conclusion, the game is very solid - if you want to play through as a muay thai fighter or something of that ilk, but if you're hell bent on finishing it with submissions etc - good luck, you're in for a ride of frustrations the whole way through.