UFC 2009 Undisputed.
At first you're like, "This is awesome! Finally an MMA game, perfect for those of us that do MMA!!!"
And it is fun at first, but the more you play it, the more you realize just how messed up the controls are. There's one button for punching with your left hand and one for punching with your right, and kicks get the same deal. But then there is a button for designating where you want the attack to go (I.E. Kicks naturally to body, punches naturally to head. Button makes kicks go to legs and punches go to body.) Then there's one button for blocking your head and another for blocking your body. Then to top it all off, if you want to do any kind of kick other than a roundhouse, you have to step in one direction first, meaning it's hard to gauge whether or not you'll be close enough to throw the kick when you throw it. Plus you have to step in a very specific way, the difference between which and a normal step is a very precise amount of time and power spent on moving the control stick, that is almost impossible to achieve. Add to this that the right toggle stick control EVERY SINGLE FUCKING GRAPPLING/WRESTLING/JIU-JITSU MOVE IN YOUR ARSENAL AND IS COMPLETELY IMPOSSIBLE TO USE, and you've got one of the worst control systems in the world.
Then we see that even though this fucked up control system is dedicated to accurately portraying a real life martial arts battle, it still leaves a lot to be desired in that category. Your fighter stands extremely rigidly in his stance and moves unbelievably slowly. While punches can be strung together nicely, any combination of kicks will ultimately fail because, again, you're pretty much limited to roundhouses, and so can't make use of some of the more useful combinations (Roundhouse, spinning back kick for example). If you can actually figure out how to use that right toggle stick, transitions on the ground are so terribly easy, as opposed to the extreme difficulty of transitions that make jiu-jitsu fun, and you don't have access to any from beyond the most basic of jiu-jitsu, and sometimes your transitions will actually take you somewhere worse. When your opponent has mounted you, for example, your only available transition is letting your opponent take your back, whereas anyone doing jiu-jitsu for more than a day will tell you that this is the single worst position any human being could possibly be in during a fight and that there is actually a very simple transition to get from under the mount to your opponent's guard.
In short, it's a fun game, but the control system is too complicated for the purpose of doing something that it still fails to do.