I just finished playing the Dead Space 3 demo on 360 and I have to say that I am not overly impressed. The section showcased was the same one from E3 2012, really action heavy, no atmosphere.
The weapon crafting system seems pretty neat though, they have essentially made it so you can carry 4 weapons but two serve as alternate fires (if you choose to have the plasma cutter rotate you are locked out of a secondary fire which brings you down to 3 weapons total) you choose from a weapon frame, a main tool and a secondary tool and 2 attachments. This was probably the thing I liked the most.
They leaned heavily on the cinematic moments and there was a QTE section (not new for Dead Space). Overall though what I played didn't impress me, there is something about fighting humans/necromorphs with guns that felt really out of place in a Dead Space game.
Has anyone else checked out the demo? What are your impressions?