I spent about four hours with Dishonored 2 last night. So far, I have to say, if you liked Dishonored, you'll probably enjoy this title even more. There is one surprise that you aught to be aware of if you buy it.
D2 is way harder on the higher difficulties! In the first game you could play the highest difficulty and figure out how to be effective in pretty short order. In this game, the AI is so alert that after an hour of play it was obvious that I needed to start over on "medium" (the recommended setting) if I was going to have any fun. At the "hard" setting (there's an even worse setting) the AI will pick you out immediately when you lean around cover if they are looking straight at you. Even from pretty far away, although, distance does help eventually. In the previous game you were effectively invisible when leaning.
It may not be as much of an issue with "high chaos" players but for players like me who like to explore and thieve in a non-lethal way it's nearly impossible to get anywhere. I suppose, if I were to stick with hard-difficulty, once I get the mark of The Outsider, I could immediately buy "Dark Vision" which would be tremendously helpful in staying behind cover and still being able to see where enemies are looking. I'm guessing that for high difficulty, stealth players, that power will become essential.