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