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