Superhero landing does no damage alot of the time (berserk) and when you do successfully kill 2 people, the achievement isnt popping and im doing exactly what alot of vids are doing, and against different groups as well as very high heights.

*EDIT*
I made it finally pop by using tranq rounds instead of non-lethal weapons, then jumped, activated and landed a little farther than what i have been trying, and it popped. This achievement/trophy is fickle for alot of people, just check any one of...

Superhero landing & Rough Landing bug