I'm currently trying to do a Smooth Criminal playthrough of Deus Ex: Human Revolution, where I kill or incapacitate all hostiles while still gaining the Smooth Operator bonus at the end of each mission. Unfortunately, in spite of cramming bodies into lockers and shoving them into the darkest corners of each room, alarms still went off halfway through the first mission, forcing a restart.
What determines whether or not a body is hidden? Is it based on the room that they're in? Or the amount of light shining down on them? Or is it based on something else entirely?
Best Answer
A body is hidden as long as no one sees the body. This includes cameras and robots.
There's really no such thing as "hidden" there's just "hasn't been found yet".
If you're talking about the very first mission (the prologue) then alarms automatically go off no matter what at certain points. They won't prevent you from getting the Foxiest of the Hounds achievement though, which requires the Smooth Operator bonus whenever you can possibly get it.
Also, there are a couple of other times in the game that alarms will be unpreventable, and again they won't prevent the achievement.