After trying the Demo for myself, I have a couple of things to point out beginning with the Nitpicks:
-The 'Options' menu is under 'Extras'? Really? Changing Settings is a luxury nowadays it seems.
-New Game-> Action Mode, RPG Mode, Story Mode... at this point I wonder if it's possible to streamline the experience even more? Nothing would suprise me anymore. Even with RPG mode you'd at least expect an inventory and equipping your squad like you could in ME 1, but no it's just 'ME2' mode basically. Did I miss something?
-The 'Do Everything Button', sure it was already featured in ME2 but now it does sprint, jump, roll, hop over, take cover, use and skip sentence! I was shocked when I was told that F was the melee button!
The stuff that matters:
I sure hope the introduction, dialogues, writing, exposition will be more substantial in the full version than the TL;DR that was the Demo. Frankly it was underwhelming, I actually laughed when the initial attack managed to kill everyone in that room except for Shepard and Anderson. Graphically speaking it wasn't very interesting with all the grey tones of the rooftops and overall sterile color palette, add to that the distractingly low quality of the textures,models,animations
or distant sprites(those running sprites...). I don't care so much about 'graphics' in Games but more about 'visual fidelity' especially in a 'cinematic experience' that is Mass Effect. (take Deus Ex Human Revolution, the facial expressions,lipsyncing, overall animations weren't all that good. But the game makes up for those issues by offering a great depth in gameplay and story). Compare the environment art from Mass Effect 1 to the environments of Mass Effect 3, it's striking I think.
On to the combat: from what I've played it's as dull as ME2 combat. You spam the very limited amount of available powers every time you can, you shoot out of cover, back to cover, recharge shield, repeat... since everything is bound to one button you may also end up rolling around or hopping like an idiot if all you wanted to do was to just get out of cover.
I miss the rich amount of available powers and options from ME1 combat, the different specialisations added some strategy to fights and you could run&gun like a badass. Since ME2 it's rather run&DIE...
I hardly play Mass Effect Games for the combat though (although t'was fun in ME1) but for the story foremost. It's hard to get a clear picture on that just from this demo, so I hope at least that the writing and consistency is better than it was in ME2.
So far the Demo did an awful job at selling me the game.