Here is the full list of all 22 Lunistice achievements.
Find all Box Buddies in all of Hana's levels
Land on the big Jerry's head
Ruin the cat slimes' vacation
Collect all Baubles as Toukie
Remove all crystals in Stage 3 - Act 1
Get all S-Ranks in all levels as Toukie
Beat the game as Toukie
Beat Stage 4
Beat Stage 5
Beat Stage 6
Beat Stage 7
End Lunistice
Collect all Cranes as Hana
Collect all Stars as Toree
Get all S-Ranks in all levels as Hana
Get all S-Ranks in all levels as Toree
Beat the game as Toree
Bonk.
Beat Stage 3
Beat Stage 2
They were kinda asking for it
Beat Stage 1