Your task for this achievement is to pickup every single armor upgrade in the game. This will probably be unlocked together with the "Seeker" achievement since a lot of the upgrades are found in hidden areas.
These hidden areas are mostly invisible wall openings which you have to touch to pass through. So you can´t actually see these passages - just run along every wall until you find all upgrades for each of the levels.
We still need a walkthrough for this game and where to find every hidden area + every upgrade. I might record them later and link the video to ta.