The game is completed when Adam boards the aircraft to leave the prison. If this is the first completion, the achievement will unlock during the cut scene that follows regardless of the choices Adam makes during the playthrough. The following video shows the achievement unlocking along with two others. Note that there is a dialog option immediately preceding the achievement unlocking. It has no effect on the achievement:
There are two other achievements that may unlock at the same time. If this is the first completion without using the Fixer Pill and/or the altered Biocell, the following will unlock:
If this is the first non-lethal completion, the following will unlock:
The above video is part of a video walkthrough (non-lethal/no augments or pill). The complete
A Criminal Past for Deus Ex: Mankind Divided video walkthrough can be seen in this YouTube playlist:
http://tinyurl.com/DE-MD-CrimPast-WT