So basically I replayed all the missions after I beat it the first time, only without killing anybody at all. I caused an accidental suicide on one of Doud's assassins so I just finished replaying the 7th mission and right after I finished it I got no achievement.
So do I have to beat the last mission again? Or was I supposed to start a new game, because that would F@cking svck since I just replayed all the missions and don't want to do it again for a while...