This achievement is done on Chapter 5:Katharsis, Area 5: The Butler
If you 've beaten the game then you should alreay have this achievement, but if not, then to get this achievement to pop you can play on any difficulty as long as you defeat the last boss which is Julius Steelwell. You should already have your walker upgrade a bit in order to take him down quickly. You'll have to dodge the robots legs while attacking, then you'll need to scramble and destroy all surrounding enemies that spawn while you're taking out Julius, and once you see that Julius health is RED, you're almost there. Continue attacking until the last health bar (RED) is depleted and the achievement will pop.
*NOTE: I will be playing through the game again so if there is any details that I may have missed or left out please feel free to send me a messege so that I may update this solution.