I started playing the demo. Jumped right in (real men dont do tutorials). I like it - lots to discover.
One question. The Austrians kicked Frederick (me) out of Dresden (sneaky bastards passed my main force on the other side of the river - but I took Prague in revenge. I like the AI so far). Frederick didnt retreat to the region in the north-west (along the road, and towards supply and the capital) but retreated across the river, to a snowy Grossenhain. This didnt feel logical.
And one remark. One of the strategic cities (Hannover) is in a region that "cant be entered in this scenario" The city is contested. I guess this area can be entered later on, or in the complete game? (I played the campaign - or is this not really the campaign, but a special scenario for the demo?).