I loved the FS2 demo. Had nothing to do with the actual campaign, but it was still pretty awesome nonetheless.
EDIT: Minor, but a couple of bugs. Most notably, you fail the second mission (but get the success debrif) if the Moloch isn't destroyed. I think I did this the first time through by telling all ships to ignore the corvette, which means the cruiser just cruised on by it and continued escorting the convoy. The cruiser made it all the way to the node and jumped out, but the Psamtik never arrived to finish of the Moloch. I'm actually not 100% sure what caused that to happen, as I got the RTB directive once before the corvette was destroyed but while the Aeolus was still engaging it, so there's a bit of an oddity there. Also:
Easter Egg: The disabled Pegasus sucks any support ships in mission straight to it. And since it's a million miles from anything, it you effectively have no support ship through that mission unless you tell the existing one to bug out and call in a new one.