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