Here is the full list of all 41 NIER achievements worth 1,000 gamerscore. It takes around 60-80 hours to unlock all of the achievements on Xbox 360.
You completed the game within fifteen hours.
You viewed the fourth ending (Ending D).
Defeat someone you care for within three and a half minutes.
Defeat the Shade inside you within three and a half minutes.
Defeat the betrayers again within three and a half minutes.
You successfully cultivated the legendary flower.
You killed 100 sheep.
You upgraded 30 weapons to their maximum level.
You viewed the third ending (Ending C).
You upgraded 15 weapons to their maximum level.
You upgraded 5 weapons to their maximum level.
Find every weapon.
Defeat Roc within three and a half minutes.
Defeat a berserking Shade within one minute.
Accumulate 1,000,000 pieces of gold.
You viewed the second ending (Ending B).
Destroy the world-saving tome within one and a half minutes.
Defeat Goose within two minutes.
Collect 50 percent of all words.
Defeat Wendy within eight and a half minutes.
Pull off a 100-hit combo.
Defeat P-33 within four and a half minutes.
You rode a boar for at least five minutes.
Defeat Gretel within two and a half minutes.
Read the final novel segment.
You viewed the first ending (Ending A).
You defeated the Shadowlord.
Defeat the betrayers within two and a half minutes.
You unlocked the key to the Shadowlord's castle.
You caught a rhizodont.
You caught one of every type of fish.
You freed Kainé from her petrification.
Emil joined your party.
Learn every type of magic.
Complete 30 quests.
You collected 50 types of raw materials.
Kainé joined your party.
Complete 20 quests.
Complete 10 quests.
Grimoire Weiss joined your party.
Pull off a 50-hit combo.