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