So here's a missions where i unlock the par time in Legendary Difficulty.
Basically you just have to run trough the mission as fast as you can trying to avoid the maximum number of ennemy/shoot.
Sorry for my english in the video, hope you will understand everything and unlock it :)
Run Time : 3:33
Difficulty : Legendary
p.s : pls tell me if the audio isn't clear enough so I will try to redo it better :D