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