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