Here is the full list of all 44 Trials of Mana achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Obtain all achievements.
Learn all abilities as any character.
Defeat Mondoragon.
Become a master cleric.
Become a master thief.
Become a master fighter.
Play with all six main characters.
Complete Kevin's story.
Complete Charlotte's story.
Complete Hawkeye's story.
Defeat Dark Lich.
Learn 20 abilities as any character.
Purchase nitromyte for the listed price.
Defeat Black Rabite.
Max out magic pot level.
Stop the end of the world.
Defeat Anise on hard.
Accumulate at least 500,000 lucre.
Become a master magician.
Become a master swordsman.
Become a master guard.
Complete Duran's story.
Complete Angela's story.
Complete Riesz's story.
Complete Chapter 6.
Defeat Archdemon.
Find Li'l Cactus in all possible areas.
Complete Chapter 5.
Accumulate at least 100,000 lucre.
Open 200 treasure boxes.
Complete Chapter 4.
First ride on Flammie.
Complete Chapter 3.
Complete Chapter 2.
First ride on Vuscav.
First class switch.
Open 100 treasure boxes.
Complete Chapter 1.
First cannon ride.
First encounter with Li'l Cactus.
First time learning a chain ability from an unexpected acquaintance.
First time learning an ability.
First time learning a companion's chain ability.
First time planting a seed.