Here is the full list of all 96 Final Fantasy V (Old ver.) achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
You defeated 2,000 enemies.
You completed the entire Bestiary.
You defeated Omega Mk.II.
You raised Lenna to level 75.
You raised Lenna to level 99.
You raised Galuf to level 99.
You raised Faris to level 75.
You raised Faris to level 99.
You raised Galuf to level 75.
You raised Bartz to level 75.
You raised Bartz to level 99.
You cleared the Cloister of the Dead.
All four characters mastered the necromancer job.
All four characters mastered every job.
You defeated Enuo.
You defeated Neo Shinryu.
You raised Lenna to level 50.
You raised Galuf to level 50.
You raised Faris to level 50.
You raised Bartz to level 50.
"You defeated Neo Exdeath without anyone in your party dying."
You defeated Neo Exdeath.
"You defeated Exdeath's servants--assassins from another dimension."
You defeated Shinryu.
You defeated 1,000 enemies.
You defeated Omega.
All four characters mastered the gladiator job.
All four characters mastered the cannoneer job.
All four characters mastered the oracle job.
All four characters mastered the mime job.
You defeated the mime Gogo.
You obtained the twelve legendary weapons.
You completed 60% of the Bestiary.
You met the dwarves.
You mastered the piano by playing all the pianos.
"You got the four tablets for unsealing the legendary weapons."
You reunited with Ghido in the third world.
You defeated Exdeath.
You defeated Gilgamesh again.
Krile inherited Galuf's power.
You raised Faris to level 25.
You raised Lenna to level 25.
You raised Galuf to level 25.
You raised Bartz to level 25.
You obtained a submarine.
You mastered lupine attack.
You completed 30% of the Bestiary.
You met a moogle.
All four characters mastered the samurai job.
All four characters mastered the dancer job.
All four characters mastered the chemist job.
All four characters mastered the dragoon job.
You defeated Gilgamesh.
You arrived in Galuf's world.
You obtained a job from the earth crystal.
You defeated 300 enemies.
You obtained an airship.
You discovered Faris's true identity.
All four characters mastered the ranger job.
All four characters mastered the bard job.
All four characters mastered the geomancer job.
All four characters mastered the beastmaster job.
All four characters mastered the ninja job.
You obtained a job from the fire crystal.
All four characters mastered the red mage job.
You earned 500,000 gil.
You completed 10% of the Bestiary.
All four characters mastered the summoner job.
You raised Faris to level 10.
You raised Lenna to level 10.
You raised Galuf to level 10.
You raised Bartz to level 10.
All four characters mastered the time mage job.
All four characters mastered the mystic knight job.
You met Cid.
You defeated 100 enemies.
All four characters mastered the berserker job.
You obtained a job from the water crystal.
You earned 200,000 gil.
You obtained a wind drake.
All four characters mastered the knight job.
All four characters mastered the monk job.
All four characters mastered the black mage job.
All four characters mastered the thief job.
All four characters mastered the blue mage job.
You found out Faris is a woman.
All four characters mastered the white mage job.
You earned 50,000 gil.
You obtained a job from the wind crystal.
You earned 10,000 gil.
You obtained the pirate ship.
You played a new game.
You earned all achievements.
You pinned your hopes on Gilgamesh.
You escaped from the final battle.
You opened all the treasure chests.