Did you shoot his parrot?
Took me hours to manage to stealth him successfully and hold him up for his camo and gun. Might buy it tonight, its on offer on PSN and I never finished it
Gonna see if there's a good youtube video that shows all of the depth of the options in that game. Still don't think its been surpassed for things like that, not enough linear games allow the player to experiment properly. Dishonored gave you a lot of options, although I think it made it a bit too easy to abuse the teleport ability, and it didn;t have the meta-stuff like using your own equipment to make an enemy ill or changing the clock