Here is the full list of all 31 Final Fantasy XIII-2 achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Obtained the highest possible result in the battle to determine the fate of the world.
Fully developed all abilities.
Befriended a most unfriendly monster.
Went the distance on chocobo-back.
Dealt 99,999 damage with a single attack.
Performed a multitude of paradigm shifts.
Defeated a powerful enemy with graceful poise.
Amassed a fortune in casino coins.
Followed the story to its conclusion.
Spent a fortune at shops.
Defeated a powerful enemy with perfect execution.
Turned your back on empty dreams and joined the battle to save mankind.
Prepared to face a test of your determination in the rift where hidden truths slumber.
Completed an entire fragment category.
Successfully used Feral Link abilities a significant number of times.
Defeated a powerful enemy with valiant skill.
Obtained five Cinematic Bonus rewards.
Fought a significant number of battles without using the "Retry" option.
Acknowledged the threat facing the world, and decided to fight back.
Performed a significant number of preemptive strikes.
Visited the place where the saviors of the past dream in crystal.
Visited the place where clues to the future lie waiting to be discovered.
Defeated an army's worth of enemies.
Staggered a significant number of enemies.
Left behind a normal life, and began a journey through time.
Responded swiftly to the appearance of enemies.
Accepted a new fate in a world where everything has changed.
Witnessed every possible Paradox Ending.
Completed every fragment category.
Defeated every worthy opponent.
Defeated a powerful enemy on equal terms.