I've downloaded it and tried it, I enjoy the concept, but the range of motion doesn't seem realistic, if you're in midair holding onto your opponent, your capacity to twist using them as leverage is limited. Another problem is that your limbs dont collide with each other, as in if your arms and legs come together, your arms will slide through your legs as if they are not there, at least some of the time, as I've noticed it happening. And finally, prolonged force application to joints is not as effective as high impact collisions, now obviously a high impact collision should do more damage, but prolonged hyper extension should also be effective, which it is not.
The motivation behind my last complaint is that during one of my free fights I almost locked the immobile opponent into an arm-bar, and if i actually manage to pull of any jiu jitsu in that game, it better be able to detach limbs.