It seems like he randomly picks one of about three moves when you hit attack, and I wonder if they have different hit properties. Luckily, there are tons of command normals, and once you get a combo started it's not random at all. It would be cool to see a combo list.
I loved the demo though. Zandatsu doesn't bother me at all - it looks and feels awesome, I just hope it's balanced to where it's not ridiculously overpowered. I never realized you could have an inventory of health nanomachines that automatically replenish you, so if you're going through like three nanomachines in a hard fight anyway, refilling your main health won't be such a huge thing.
I shouldn't have played the demo though since I know I'm getting this game.