Overall, I really like the demo A LOT. There've been some massive changes introduced which I really didn't see coming after the previews and interviews, especially the completely revamped defending. This will probably be the toughest detail to master for me, spamming the A button/now X won't do shit any longer. It's all about the right timing now.
The speed of the game also seems fine to me. As most of you, I got used to playing on Slow, but Normal feels pretty realistic in this demo. Same goes to the slighty improved weight of the ball.
I'm still unsure what to make of the Impact Engine, though. There are moments where it really, really shines and improves the atmosphere by a whole lot, but on the other hand, I already conceded and gave away way too many penalties because of it. Here's hoping they're somehow able to nail it, otherwise it could turn out to break more things than it originally intended to improve.
Still, as I said, my overall feelings are very, very positive. It feels completely different compared to FIFA 10 and 11, which I would consider to be a very good thing in terms of making the game better/more strategic. The major thing left they really need to sort out next year should be the AI. Doesn't seem they've put too much effort into improving the awareness of the players.
Anyway, can't wait for the full version to arrive now. So far, I'm a happy camper.