At one point (1:24-1:28 in the vid) there are two wolves running towards him. He takes the ice attack in his left hand and aims it at the ground creating what appears to be a rune. This rune is activated when the wolves run over it, killing them both. Was this a normal magic attack, that when aimed at the ground becomes a rune trap? Or is it a rune spell that he just so happened to have equipped at the time?
Later (3:05-3:25) he is using normal shock attacks against a Draugt Deathlord. When it comes close, he uses a shout to slow down time. Then, using the same spell in each hand, the same spell that was just a normal shock, he aims at the ground next to the enemy and it causes a shock explosion that sends the enemy flying. Are we now to assume that dual wielding spells adds a bonus effect to it? Remember, Todd Howard, when talking about dual wielding spells in the first demo video (1:50-2:06), only mentions that it creates a bigger and more powerful spell. But we can clearly see in the second video that it has added an additional effect.
I personally am hoping that aiming certain spells at the ground will create runes rather than having separate rune spells. I am also hoping that dual wielding spells have bonus effects to them, as well as being more powerful.
I know there is no way to confirm anything I mentioned, I'm just bringing it up for discussion.