Here is the full list of all 49 WORLD OF FINAL FANTASY achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Completed 10 intervention battles.
Defeated the Undead Princess 10 times.
Defeated the Princess Goblin with the Warrior of Light.
Got to the bottom of the “phenomenon” at the Coliseum.
Recorded a large number of Mirages in the Mirage Manual.
Found the first key from the Crimson Prophecy.
Battled 100 times.
Won your first Coliseum battle.
Obtained your first Champion Medal.
Defeated your first murkrift Mirage.
Completed your first intervention battle.
Fulfilled a townsperson’s request for the first time.
Repelled the Bahamutian Army.
Imprismed your first Mirage.
Arrived in Grymoire.
Obtained every achievement.
Reached an ending.
Reached the true ending.
Found all of the keys from the Crimson Prophecy.
Learned the location of Castle Exnine.
Recorded a huge number of Mirages in the Mirage Manual.
Recorded an inconceivable number of Mirages in the Mirage Manual.
Recorded every last Mirage in the Mirage Manual.
Mastered your first Mirage Board.
Mastered 100 Mirage Boards.
Obtained every last Champion Medal.
Battled 500 times.
Opened 100 treasure chests.
Opened every last treasure chest.
Defeated every last murkrift Mirage.
Found the secret area in every dungeon.
Completed 30 intervention battles.
Completed every last intervention battle.
Fulfilled the requests of every last townsperson in need.
Joined forces with Shivalry to defeat the Golden Flan.
Chastised the fugitive Ifreeta.
Defeated Ultros in Tometown.
Teamed up with Gilgamesh to stop the Bahamutian soldier.
Brought all seven of the Pleiad back in line.
Added Tamamohimé to your roster.
Defeated the Quacho Queen with one of Lann’s attacks.
Defeated 30 teams at the Coliseum.
Defeated every last opponent in the Coliseum.
Braved and completed the new dungeons that appeared.
Defeated the Cogna known as XG.
Defeated many foes using any Magitek armor.
Cleared the sky of uncountable einhänders.
Reached the final chamber of the Nether Nebula in record time.
Thwacked a whole bunch of cactuars in a single thrashing.