I'm not sure how much more to expect, but according to one interview the demo didn't include everything. Apparently there will be more moves and more awakened states. So the combo system might go a little deeper. Also from what I understand you will be allowed to assign whoever you want to the shoulder R1 and L1 buttons, and that R1 I believe will have your ally do a melee attack and L1 a jitsu (or vice versa, forget which it is). So sounds like using your friends and putting them on the button that suits them most could add some strategy as well.
Also something happened yesterday that I didn't realize you could do. I did a charge up punch on the computer (hold o down, goes into a cinematic when you hit with their face contorting) and it sent the comp flying back onto that rock structure to your left when you start out. The comp actually stayed on it and I hopped up, so apparently you're not just limited to the grass and water, but can fight on the walls as well. I just thought it was a nice touch.