This solution isn't so much of a 'locator' as it is a description of the achievement requirements.
For the 100%, you will need:
-The complete all stages and bosses, including the final boss
-Collect all 9 ores (keep in mind you only need 8 for all upgrades, so if you have upgraded everything and have no ores left, you are still missing one)
-Purchase all upgrades (sword, bow, health, quiver and wallet)
-Collect all story related items (orbs, powerups, and fang)
-Activate all portals (not 100% if this is a requirement, but you will undoubtedly activate them on your way to everything else.)
- You DO NOT need to collect all the brown chests that are hidden across the world (although their contents will assist in purchasing upgrades).
Like most progressive Xbox One achievements, you can check your progress by viewing your achievements from the achievement tab. You should be at 78-80% (seems to vary) if you have everything prior to the final boss fight.