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