Anyone know if it is one hit kill?

it depends on where you hit as far as I know. In the face it is, in the neck, it is, and the leg it won't etc.
If you see the gameplay vids, it SEEMS it's like I said, hit the vital points and it's one hit one kill

Possibly be headshots and sneak attacks. other than that you'll propably have to use the exploding bolts, or upgrade your crossbow.

And i guess i also comes down to which enemy you are shooting at.

Thanks for the info.

It will be vital for a stealth assassin. lol

Meh, as long as i have my blade, i'm happy(and deadly)

Lol couldn't agree more, shooting a guy in the foot, hoping he would die, will not only alert him of your presence, it will also seriously piss him off rofl

Now I wonder if the guy would actually scream and alert the others.
Then even if you remain hidden, the guards will be more alert because someone was just shot.
Probably so, I have very high demands for this game but I feel like they can live up to my expectations.