I'm not sure if anyone has mentioned this, because I can't search the forum as I am on mobile. But I noticed that in the extended demo at 8:04 the player seemingly on command of a button leans and the camera pans further to the right in order to see around the corner in order to observe an enemy in the parallel room. Also at 12:53 when Joel hears the last enemy behind him he quick turns 360 degrees to aim at the noise before the enemy jumps out with the Molotov. If this had already been mentioned please let me know. May 7th hurry up!
Hmm, maybe there are camera assists in single player? But I doubt he turned 360 degrees, probably just 180
It would have helped to at least have the video embedded in your post. Or, at least mention what video you're talking about. haha. But i wasn't lazy so i took a look, anyway. So, the leaning thing just may be automatic when you sneak around corners, or there will be a button for it. The 180 degree turn would most likely be a feature, and it's probably just done by pulling back on the movement stick and tapping on the aim button or some other button.
The leaning is most likely part of the cover system, as in, you press a button to go into cover, and move the stick which ever direction you want to look. As for the 180 "about turn" I bet it's something like RE4 where you just pull back on the stick and press a button (probably whatever button we'll be using to "walk fast" for sprint) that does the 180 turn.