^Mate, I don't know what you were expecting, but it's just a demo of an RPG game, not an RPG in and of itself. I'm GLAD it was focused on just the new combat mechanic with only skirting references to any actual story content. This thing is meant to attract *new* players who may not have played Mass Effect--or any RPG for that matter--before. Fans of the franchise already have an idea where things are so there's no need to go over old ground. As for connecting to the end of ME2; again, it's a demo. I'm sure what we have here is a cut down version of the final product's beginning.
Next thing you'll be complaining that film trailers are too short, don't tell a complete story and have "endings" where nothing is resolved...
I understand you're excited about the game. If you don't think there's anything to worry about, that's fine. But as a fan of the original Mass Effect, I have some concerns about ME3. As this is a forum, I feel compelled to express those concerns. If you don't like it, too bad. Deal with it. Your aversion to any sort of criticism doesn't make my impressions of the demo any less valid.
Quite frankly I'm tired of people on the Internet attacking people with negative opinions about things. We ought to be able to disagree and still be civil and constructive ...