Full list of all 18 Final Fantasy achievements worth 200 gamerscore. It takes around 50-60 hours to unlock all of the achievements on Windows Phone.
Defeated Chronodia in all forms.
Defeated 5,000 monsters.
Defeated Warmech.
Completed entire Soul of Chaos.
Completed the 15 Puzzle within 30 seconds.
Completed game within 8 hours.
Defeated Chaos.
Defeated Tiamat.
Set foot in every monster-free town and castle.
Defeated the Kraken.
Acquired the Airship.
Defeated Marilith.
Acquire 100,000 gil.
Defeated the Lich.
Defeated 1,000 monsters.
Took 10,000 steps.
Defeated 100 monsters.
Crossed the bridge north of Cornelia.