Here is the full list of all 63 Neon White achievements.
Complete Yellow's Heaven Rush
Complete Violet's Heaven Rush
Complete Red's Heaven Rush
Write Green into the Book of Death
Complete 100% of the game
Earn an Ace medal on every level
Unlock one last memory
Restore Heaven
Complete Mission 12
Write Green into the Book of Life
Defeat Green at the Hand of God
Collect all gifts
Complete Mission 11
Unlock all of White's memories
Complete your relationship with Green
Complete your relationship with Red
Complete Red's Sidequests
Complete your relationship with Mikey
Complete your relationship with Raz
Complete your relationship with Violet
Complete your relationship with Yellow
Use the Book of Life Card on a Mimic
Redeem every Heavenly Delight Ticket
Complete Mission 10
Defeat Green at the Third Temple
Defeat Green at the Third Temple before he reaches the final stage
Complete Violet's Sidequests
Complete Yellow's Sidequests
Complete Mission 9
Complete Mission 8
Complete Mission 7
Find a Strange Coin
Die from a Mimic's bullet
Complete Mission 6
Earn 50% of the total Ace medals
Collect 50% of the total gifts
Get killed by a Tripwire
Defeat Green at the Clocktower before he reaches the top floor
Unlock one of Violet's memories
Unlock one of Red's memories
Complete Mission 5
Unlock one of Yellow's memories
Complete Mission 4
Defeat Green at the Clocktower
Discovered Idiot Island
Complete Mission 3
Deplete the Fists card
Use the Fists card
Stomp off of the edge of a level
Collect ten cards from vending machines
Complete Mission 2
Redeem a Heavenly Delight Ticket
Give your first gift
Complete Mission 1
Kill an enemy by parrying a bullet at them using the Katana card
Earn your first Ace medal
Complete White's Heaven Rush
Complete White's Hell Rush
Complete Red's Hell Rush
Complete Violet's Hell Rush
Complete Yellow's Hell Rush
Complete Mikey's Heaven Rush
Complete Mikey's Hell Rush