Here's my review of the demo after playing it multiple times:
The Graphics The graphics of the game have dramatically improved since ME2. Character faces and armor looked much better, Wrex looked awesome to be specific. The environments are just beautiful. Earth was nice, but Sur'kesh was just stunning.
Character CreatorI'm a bit mixed about the new creator. At first I like the new hair options and the new colors, but some of the facial features are shaped differently. I don't know how this is going to translate when I import, whether it will update to the new shape or keep the old. I rebuilt my usual custom shepard with the exact same specifications as previous games, and to my surprise, and amusement, I came out looking like David Silverman.

The new hair options and colors are nice, but hopefully I'll be able to import my shepard's face without having it change the shapes of the eyes and nose. Luckily for Mr. Silverman, it's possible to make a Shepard look exactly like him.
CombatI was pretty pumped up for the game after seeing the improvements in combat that Bioware's been showing, especially for the multiplayer beta hitting next tuesday (for those of us who preordered BF3). But after playing the demo I'm not that excited. The combat seemed very clunky and buggy. It was difficult to actually shoot someone, for whatever reason. I'd put the reticule on an enemy, fire, and nothing happened. I had to shoot on different parts of the body like the leg or head to actually register a hit. My last run through I played a Vanguard, and the Biotic Charge was either buggy, or intended to be difficult to work. I would target an enemy that's standing out in the open, press the button, and nothing would happen. This came up numerous times where I had an enemy who decided to pop out of cover, and I couldn't charge them. While I felt it was a bit clunky, and was having problems using the Biotic Charge, I did enjoy the Vanguard's heavy melee, and Nova power. Those were very fun.
MusicI was a bit mixed for the music as well. Some I loved, but some jus didn't feel like it belonged in ME. The music that plays when you're defending your position waiting for the Normandy is a good example. It just didn't feel like Mass Effect. Now the music during the cutscene where you're leaving earth and see the reaper blowing up the cars, that was perfect. It sounded like it belonged. I love that piece. The music throughout Sur'kesh was epic as well.
Sound
The sound team deserves a lot of credit, because this game sounds like pure gold. I was blaring my speakers to the max while doing my run throughs on this, shamelessly. The reaper sound is awesome. Could play it as music. The weapons and powers sound are incredible, and give it more of a punch, it makes the weapons/powers feel more deadlier. Hats off to Rob Blake and the sound team.
RPG ElementsThe RPG elements are back in this game, and are very strong. There are a lot of options to take when evolving powers, and the weapons customization seems like it's gonna be variable. I picked up a bunch of mods, but couldn't find a mod station though. :/ Don't know if they took it out of the demo.
DialogueIf you've seen my posts this week on dialogue, you probably know what's coming. I've had issue with the beta due to the HUGE amount of automatic dialogue and two options of paragon or renegade when rarely given the chance to choose. I figured I'd wait until the demo came out to see if it's the same, and it is. The amount of automatic dialogue in this game is worrisome to me, because part of what makes this game interesting is choosing what to say and defining each individual character through dialogue. Shepard seems to be his/her own person now, with rare instances of player input deciding whether you're going to have a positive or negative response. I'm hoping this was for the sake of the demo, but not exactly going to hold my breath over it. Needless to say, those of us who loved the feature of role playing our Shepards in previous games aren't going to be to pleased if the demo is indicative of the retail game. It was frustrating to see Shepard talk to npc's without player input, and then once or twice out of an entire conversation choosing whether we'll be nice or mean. It's my biggest complaint about the demo.
There it goes.
-Polite