I heard you play as one of the masked dude at the very first part of the game, y' know the one that blinks from roof to roof. It's not confirmed yet though.
Right! That one.
Since we are playing as the bad guys, I hope I can kill anyone freely now.
I know its not on the trailer you posted but I also hope they can summon rats too. :3
When I was Corvo I tried not to kill guards cause they weren't guilty. It was their job and stuff. People who annoyed me or were assholes I killed them. I spared people who were nice or asked nicely to spare them. I tried only eliminating weepers and targets. I spared some major targets like lady Boyle but I found out a funny bug or secret. If you choose to spare her and knock her out you have to carry her to a ship and place her there and the guy will thank you and go away promising me that I will never hear from her again by going far away. So I threw her from the stairs in to the boat and she died. But the NPC bugged and thanked me for sparing her and went away too. It doesn't work if you kill her while she is in the boat. Only by throwing her in to the boat she will die from the fall damage and the special non-lethal quest will be complete. It was my favourite quest. I had low-chaos ending though the high-chaos ending was cooler.
Same, I do not kill anyone unless I really have to.
Except when I'm out of sleep darts and I have to face a few weepers, I usually leave them alone, trying to incapacitate them from behind is risky since I didn't upgrade my health at all, lol.