Here is the full list of all 35 Final Fantasy XIII achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
Took the first steps toward challenging an unjust fate.
Survived the Purge to confront a greater peril.
Strode into danger's den and paid the consequences.
Slipped through the net and lived to fight another day.
Resolved to be more than a victim of circumstance.
Evaded pursuers, though memories of the past still gave chase.
Made plans to infiltrate enemy-occupied territory.
Carried the burden of guilt to the end of the line.
Took the fight to the enemy's door.
Recognized the true threat to the world's future.
Traveled to the world below, seeking a way to alter fate.
Defied destiny's charge and embarked on a different path.
Witnessed the dawn of a new crystal legend.
Took over 10,000 steps on the lowerworld surface.
Completed all low-level Cie'th Stone missions.
Completed all mid-level Cie'th Stone missions.
Triumphed over undying lowerworld souls in seven fierce battles.
Toppled a green terror and cut an oversized succulent down to size.
Passed Titan's trials.
Completed all high-level Cie'th Stone missions.
Completed all Cie'th Stone missions.
Earned a 5-star rating for all Cie'th Stone missions.
Mastered the Commando role.
Mastered the Ravager role.
Mastered the Sentinel role.
Mastered the Saboteur role.
Mastered the Synergist role.
Mastered the Medic role.
Dealt 100,000+ damage with a single attack.
Felled a heavyweight of the lowerworld wilds.
Fully developed all characters.
Discerned the full attributes of 100 enemies.
Earned a 5-star rating in the battle to determine the world's fate.
Discovered buried treasure with a little help from a chocobo.
Held every weapon and accessory.