Here is the full list of all 21 Saga of the Moon Priestess achievements worth 1,000 gamerscore.
Defeat 50 foes.
Defeat 150 foes.
Defeat 300 foes.
Collect 150 beads.
Collect 300 beads.
Collect 600 beads.
Defeat the boss of the Forest Cave dungeon.
Defeat the boss of the Mountain Dugout dungeon.
Defeat the boss of the Desert Sanctuary dungeon.
Defeat the boss of the Forgotten Gravesite dungeon.
Defeat the boss of the Frozen Ziggurat dungeon.
Find the Gloves on your journey.
Find the Bow and Arrows on your journey.
Find the Bombs on your journey.
Find the Fire Staff on your journey.
Find the Swap Chain on your journey.
Buy an item in the shop for the first time.
Find a map for the first time.
Encounter the Mermaid for the first time.
Have your fortune told for the first time.
Free the prince from his prison.