Full list of all 48 The Messenger achievements worth 1,250 gamerscore. It takes around 15-20 hours to unlock all of the achievements in the base game.
The base game contains 40 achievements worth 1,000 Gamerscore, and there is 1 DLC pack containing 8 achievements worth 250 Gamerscore.
Be lectured on happiness
Beat the game
Defeat Phantom
Complete the melody
Survive the Corrupted Future chase
Enter all areas
Defeat the Demon King
Keep a windmill shuriken going for 15 seconds
Destroy all Power Seals
Complete the Elemental Skylands scenario
Execute 15 Cloudsteps without landing or clinging to a wall
Rescue all Phobekins
Run on lava
Bump on a few flowers in Rivière Turquoise
Receive the Key of Love
Kill a green demon in a single hit
Buy all upgrades from the shop
Make it out of the underwater labyrinth
Be lectured on the inner child
Ride Manfred around the world back to where it all started
Defeat the Demon General
Defeat the Sky Serpent
Time travel to the future
Defeat the Arcane Golem
Get to the top of the mountain
Be lectured on the power of stories
Defeat Colos & Suses
Defeat the Queen of Quills
Defeat the Emerald Golem
Jump down the big waterfall in Bamboo Creek
Defeat the Necromancer
Buy five upgrades in the shop
Buy the Swim Dash upgrade from the shop
Attack your enemy projectile
Destroy a big Time Shard
Destroy your first Power Seal
Meet Quarble
Complete Ninja Village's intro
Make it through the Dark Cave without the 'Power of True Sight'
Make it from the beginning of the game to beating the Queen of Quills with zero deaths
Make your first purchase at the Craftman's Corner
Unclog the Money Sink
Defeat Octo
Defeat the Voodoo Totem
Defeat the Demon General... Again
Win the race with a perfect score
Meet the voodoo mask
Accept 'THE DEAL'