You should unlock this during a 3rd play thru of Hard mode around Area 5 or so.
However, this achievement is buggy. I had played thru the game over 10 times from start to finish and was unable to unlock the achievement. In the event this happens to you too, I would recommend earning the other achievements first and then trying the following...
Go to your Steam Folder (C Drive) or Steam Library (If another drive like E), then thru the following folders: steamapps, common, FullBlast, FullBlast_Data, and finally Data.
You should find a single file called 'Preferences'. Delete that file. Deleting that file will clear all save data and reset progress toward any locked achievements.
Hopefully this helps others unlock this buggy achievement!