I agree, the depth of this is very impressive - the use of the right analogue stick is very well implemented to offer things like a skilled escape from submission which leaves you in a better postion than the 'brute force' escape which repeated punching offers.
Graphically, this game is fantastic, with very believable injuries and flawless collision detection... each hit feels very dynamic, with some glancing off and others connecting with a very satisfying feel.
Although only 2 fighters are available in the demo, it is clear to see how much variety there is within the game for different fighting styles. I have already won bouts by knockout, TKO (the ref stepped in after I landed an undefended string of face punches to my floored opponent) and submission, with a very satisfying blend of standing and ground combat.
I like that it really captures the 'cat and mouse' feel of UFC, with no fight ever being 'over' no matter how much of a beating one fighter has inflicted on the other. I took an absolute pasting standing up, with blood streaming from my face, only to dodge a high kick, take down my opponent and then landed a flurry of punches to produce a dramatic turnaround victory.
This game has genuinely taken me by surprise and is going to dominate my weekend...