Here is the full list of all 28 MAGICALSPIRAL achievements.
Win the fight against Sobel.
Win the fight against Undine.
Win the fight against Sylph.
Collect every chest.
Win the fight against Haokah.
Avoid all the lightning in Thunder and Lightning.
Win the fight against Flower Golem.
Avoid all the rocks in Collapsing Cave.
Don't use any items.
Never retry from a game over.
Kill 50% of all monsters.
Get up to a 10-hit combo.
Win the fight against Salamander.
Find the gold chest in Sobel's Stage 1.
Find the gold chest in Sobel's Stage 2.
Find the gold chest in Sobel's Stage 3.
Find the gold chest in Sobel's Stage 4.
Find the gold chest in Sobel's Stage 5.
Win the fight against Medianne.
Defeat the Selector as Medianne.
Defeat the Selector as Sobel.
Defeat a number of monsters in Going For A Swim.
Don't open a single chest.
Don't kill any non-boss monsters.
Kill every monster.
Get up to a 30-hit combo.
Beat any route within 30 minutes.
Get up to a 50-hit combo.