Here are two trailers from August, the first tells how the stealth system works and how to use it to your advantage, the second is a showcase of some of the many different ways you can dispatch your enemies.
The Study of Stealth Trailer
What caught my eye: this game is bringing me memories of Metal Gear Solid. That maneuver where he plucks the harp to attract the enemy, before jumping up on the chandelier, then coming back down to take him down from behind was impressive to say the least.
Creative Kills Trailer
What caught my eye: this one shows how much the geniuses at Bethesda were thinking outside of the box when making this game. All three aspects (Death by Rat, Friendly Fire, and Reversal of Fortune) are batshit crazy and unlike anything I've seen.