My favorite way is to play through on pro with the goal of getting silent assassin on each level but being willing to salvage the mission if need be, trying to focus on least number of witnesses first then minimizing collateral damage. If anyone else has ideas to increase the life of this game while we wait for absolution please post up.
Man who hesitates is not only lost but also miles from next exit
^ I have actually killed a good majority of individuals in the elevator trap on You Better Watch Out. On pro. I got 47 kills this way too without ever setting off an alarm. Just suspicion. Keep the bodies on the elevator roof, none the wiser. Shoot the bottom of the hottub on the way out completes your objective too.
I can't believe I live in a country where Casey Anthony will make more money than me