Here is the full list of all 21 Before the Echo achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
See the hidden ending.
Learn all spells.
Defeat an enemy on the seventh floor using only Arclight.
Defeat an enemy within eleven seconds.
Defeat an enemy with less than one second remaining on the clock.
Queue up five spells in a row.
Synthesize Iridium.
Synthesize every recipe in the game.
Discover the name of she who controls fate.
Beat the game on any difficulty.
Obtain every droppable item in the game at least once.
Successfully complete a synthesis at 25% odds of success or lower.
Trigger Boost a Trigger Boost.
Defeat an enemy using only poison spells.
While learning a spell, achieve 100% accuracy for the entire song.
Get her back.
Defeat the Holiday Whompa.
Obtain all three droppable items from any single enemy.
Recover over 150 mana in a single battle, and win.
Complete a battle without failing a spell.
Successfully defeat your first enemy.