Have played through some of the demo (just started the Salarian scenario), and impressions are mixed.
The graphics are a little odd, the animations in particular. The total lack of upper body movement was something that I found very offputting... is like Shep's just hovering through the levels instead of walking, and actually SEEING Anderson move through his feet almost exclusively was... distracting, at times. Particularly since his feet never seemed to touch ground.
I found the shooting itself quite fun. I loved the responsiveness of it: being able to change the rate of fire so much and pop 12 or so rounds into someone in half a second is very satisfying.
The dialogue... I'll admit, I was skeptical when I heard about the three-experiences-in-one approach Bioware was taking with this game. I couldn't see how you could just "turn off" such a crucial aspect as dialogue for action mode, not without there being some pretty large concessions in just how much or how prominent or the ways in which dialogue was used. But, is my dissatisfaction with the dialogue (which seemed very basic and cheesier than all get-out to me) indicative of demo-hood, or something to do with the basic way the game is put together this time? don't know. So... no real answer to this question was provided by the demo for me.
the one-button-to-rule-them-all approach, I find, might just be a bit TOO convenient. Found myself, toward the end of the first level with Anderson, looking at the game as merely telling me when to grant it authorization to do the appropriate thing, a simple Yes/No switch, rather than me using Shep to actively opening a door or pick up a med kit or something. I didn't even need to know what the in-setting action was going to be: just push the button and everything will be fine. The game was... remote, in that respect. Distanced. Unengaging. Didn't much like that aspect of it. Simplicity has it's place, granted, but in this case I feel that making it THIS simple just lets the game play itself. From here it's just one short step to removing the player entirely.
Cut scenes still had a tendency to surprise me. I didn't notice them intruding to the extent that they did in the DA2 demo, where at least one didn't even let me finish the battle I was in at the time, but the demo still imposes itself too much in this way for me to really enjoy it. Is like I'm fighting with some other player for game time.
I know that some of these issues are demo-specific, while others are Bioware-specific, and it's entirely possible that I'm simply "not getting" the way Bioware demos are put together -- or that Bioware just isn't targeting me as an individual -- but both this demo and the DA2 demo have come across rubbing me the wrong way. This one's better than DA2's, but still... mixed impressions. Most of them mildly negative.
Will play the demo again, though, and see if I just missed it last night.