It shows the Reapers as well as teasing some boss-like events in the trailer. It reiterates that we decide how the war is won in the last entry to the trilogy.
BioWare confirmed this week at Microsoft's E3 conference that Kinect would be supported, or rather it's microphone would be used to issue commands to squad mates, fire off abilities and even select lines of dialogue. Surely this will come to PC as well then?
Mass Effect 3 releases on Xbox 360, PS3 and PC in early 2012.