Just as would be assumed sight and sound will be key factors in moving about for the quiet kill. So no real big news there. For those who don't get that, enemies will have a cone of vision you must avoid and your movement will make sound based on how fast you move and surfaces. So nothing all that new to the stealth part of games. Not even the fact that you can make sounds to lure or distract to aid in all the sneaking.
After seeing this I have one blaring question, where are all the cool powers making him a supernatural assassin? Blink (Teleport) and Possession are going to be handy, but is that all we get to stay hidden while we murder people? No zone of silence? No decoy? Are these going to be hidden in game for some reason? Time will tell.
While you wait for time to tell, here's the trailer showing some stealth options.