I think the difference in the first game going from the very small snippets we've been presented with of the second, is that you were often stumbling upon events after they had happened. Not just the bad things but good things too. There was a sense that something good/something terrible
had happened here but at a time before the player arrives. You would see scenes of great violence but you'd seeing the relics of it strewn across the scenery and piecing together what happened in your head.
How many times did you enter a building and Joel or Ellie would comment on what they thought had happened there? How many times would you find a document that hinted at a grisly fate and then see little hints towards it as you progressed through the environment. Or found the result yourself later. Very often, the player was not an active agent, participant or spectator in these events. Just a curious bystander making their way through, but with another goal in mind.
I actually played through the game for the first time this year, half in March, half just a week or so ago. Off the top of my head, I can't remember that many violent scenes, certainly nothing explicit as in that trailer. And when I say "explicit" I don't mean in a sense of being rude or outrageous, I mean as in the fact it's blatantly shown and spelt out to the player. Bar the random times you club infected/bandits over the head with a pipe or something, I can think of:
An example of how you know great violence has occured by never get shown it, is
Of course the in-game.combat is violent, but that definitely serves a purpose. The crunching, violent combat makes you feel each hit. Not only in the force of the blow but also what it's costing you perhaps in surprise, in exposing yourself to other enemies, and I guess also what it's costing the main characters each time they kill.
As I said in the conference thread, I think TLOU is a very slow, melancholic game. I think it's very reflective and nostalgic. I think a lot of that is due to what I mentioned before about always being a bystander to things. Always coming across events after they've happened. By effectively being a wanderer, trying to go from A to B with a certain goal in mind, but being waylaid by circumstance.