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