Got the demo 3 days earlier, and TBH I was in two minds about playing the Single player portion, because I thought it may spoil it for me. I decided to give it a blast anyway!
The first notable change is the difficulty options, gone are the traditional "easy, medium & hard" options, instead Bioware have changed it to :
Action Mode : For those who want to emphasize action and combat and minimize story management. Action mode will set automatic replies in conversation and a normal difficulty.
Story Mode: For those who want to emphasize story immersion and minimize combat pressure. Story mode will set manually-selectable replies in conversation and a minimal combat difficulty.
and,
RPG Mode: For those who want to explore both realms of story and combat. RPG mode will set manually-selectable replies in conversation and a normal combat difficulty.
RPG mode was the one I picked, its a mode for people who enjoyed the original Mass Effect...which I obviously do!
The sp section contains 2 parts of the single player game. You start off on Earth, as Shepard, who has been stripped of his rank, following the outcome of The Arrival DLC from Mass effect 2. Reapers attack Earth, and along with Admiral Anderson, you have to escape to The Normandy. It introduces you to the new cover system, as well as the new heavy melee attack, (each class has a different one.) I played as Soldier class, which gets a holographic sword!!
The next part of the demo takes you to the Salarian homeworld, where you have to escort a fertile female Krogan to your ship (fans will know that the Krogan where made infertile by the Salarians!). This section is very combat heavy, pitting you against Cerberus commandos. The AI of the enemies has been drastically changed. Where as in ME1, the enemy would rush you, making it easy to kill them. In 3, they take cover, work as a team and try to outflank you. Powers have been changed too. Now you get frag grenades, which are cool
Overall, from what I've played, I'd say Mass Effect 3 is going to be an epic game. Bioware have been very careful not to ruin the game. The demo took me an hour to do. (would have taken me less, but I kept dying at a boss battle!!)
The multiplayer sections won't be live untill the 14th. (if you used the online pass for BF3) or the 17th if you haven't.
I cannot wait for March 9th...just need to finish Mass Effect 1 as a paragon, then use both characters for Mass Effect 2!!