Hehe, I love DDR (and ITG), but that isn't DDR , its Pump It Up.
DDR doesn't have diagnal arrows, or a middle button.
It just has 4 arrows, up/down/left/right.
Hes doing freestyle though, and its not what most do
If you want to see real DDR skills, and actually getting AAA's etc which is the entire point of the game haha, search for Adam Styles in YouTube.
I can play those songs he's on, but could never get AAA's on a pad, though I can on keyboard (but thats missing the point).