Must be 20 levels in one go, does not stack with multiple runs.
This guide will require you to have played enough to find and unlock different enhancements. Pretty easy to do once you've been playing for a while. When I got this, my damage and health stats were in the level 20s, I also bought all 10 Enhancement slots.
My recommended loadout is:
Weapons are Plasma Assault Rifle or the Plasma SMG.
Abilities is Cluster Grenades
Starting Enhancements are NanoEdge SkinWeave, Chiphow AmmoArt, & Armocore Attractor Grenades.
Chair Asset Energy Shield or Riot Shield
Once you're in the game, start loading up on movement speed, damage reduction, and rate of fire Enhancements, as well as Duramax Subdermal Armor to make rocket troopers easier if you're having a tough time with them. Take any bonus room available as you will usually find those first before the actual exit, cutting down your time and risk.