Here is the full list of all 32 The Metronomicon: Slay The Dance Floor achievements.
Defeat every arena challenge.
Defeat every arena challenge on hard.
Beat the final challenge's omega boss.
Purchase every ultimate weapon.
Deal at least 5000 hp damage in one strike as Gwen.
Survive a story song without healing any party member.
Survive a story song without killing an enemy.
Succeed in every single sidequest.
Survive every song in Story Mode.
Survive every song in Story Mode on Hard.
Save the world of Koras from Dancemageddon.
Decompile a fearsome Dance-o-bot.
Unlock Sara's laboratory.
Kill five enemies in a row with a single attack.
End the dancing of a great Candy Dragon.
Make five arena challenges your chump
Succeed in beating five sidequests.
Conquer one challenge in the school arena.
Dethrone the Wraith King in the Haunted Kingdom.
Perform a perfect Solo-Lane Team Attack.
Succeed in your first story sidequest.
Survive your first 10 songs in Story Mode.
Destroy the Speyeder of the Wild Forest.
Unlock your first bonus song.
Attain a 300 note streak.
Perform your first upgrade to the school.
Perform a perfect meteor attack counter.
Attain a 100 note streak.
Apply six buffs to one hero at the same time.
Beat a fifty song playlist without ever pausing.