Here is the full list of all 38 Pile Up! Box by Box achievements worth 1,000 gamerscore.
Play the tutorial
Explore all Boxling Square
Pick up every collectible in the game
Pile 5 boxes
Pile 10 boxes
Pile 20 boxes
Throw a pile of 10 or more boxes into the water
Carry an item through 10 consecutive rooms
Build an autonomous flying box
Play every arcade game
High jump: heavy dash and jump!
Long jump: dash and jump!
Destroy a pile of at least 10 boxes
Put on a new outfit
Finish the game faster than the Seed by Seed record
Buy every costume
Scare every spider in the game
Complete a world without falling
Fall 100 times
Strike a pose on a pedestal
Listen to a musical performance by some slimy friends
Open the bonus route in Frogipelago
Complete Frogipelago 100%
Open every beach umbrella
Watch a movie with upside-down friends
Open the bonus route in Citizen Cave
Smash every squash in the game
Complete Citizen Cave 100%
Enjoy some fireworks with spiky friends
Open the bonus route in Forest Fair
Move the wall of boxes to another room
Complete Forest Fair 100%
Watch a performance by colorful friends
Open the bonus route in Feather Theater
Complete Feather Theater 100%
Do something horrible...
Bounce a trampoline ... on a trampoline!
Unlock all other achievements