Here is the full list of all 25 Poi achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Kick a Bucket Head.
Collect all the Explorer Medallions in Mount Magma.
Hey, watch where you're rolling!
Collect 10 Explorer Medallions.
Collect all the Explorer Medallions in Cozy Canyon.
Discover the mysterious travelling merchant.
Find ALL the Fossils.
Do a triple jump.
Purchase an item from the shop.
Sometimes, things don't always go as planned.
Earn your first Explorer Medallion.
Collect all the Explorer Medallions in Sinking Sands.
Collect all the Explorer Medallions in Crystal Cavern.
Find the legendary treasure.
Beat the game in New Game+ mode.
Collect ALL the Explorer Medallions.
Find all of the hidden costumes.
Find a hidden hat.
Visit the hidden planet.
Meet the requirements to open the Mysterious Gate.
Rescue all the baby Pin Birds.
Discover ALL the Locations.
Find ALL the Golden Gears.
Take a picture of ALL the creatures.
Take a picture of the Master Explorer.