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