Here is the full list of all 49 Atelier Ryza: Ever Darkness the Secret Hideout achievements.
Created an item with Item Level 99.
Got Ryza's alchemy level to 99.
Obtained all recipes.
Obtained the Revelation Book.
Defeated all 5 Great Elements.
Defeated the Noble Paladin.
Defeated the Eternal Sculpture.
Defeated the Mirage Master.
Defeated the Savage Assassin.
Wrote a record of every exploration.
Found all treasure chests.
Wrote a record of one exploration.
Saw everyone move on to chase their dreams.
Created the Crimson Stone and saved Kurken Island.
Defeated the King of Storms.
Completed requests to get Peter to interview you.
Defeated the Queen of Darkness.
Defeated the Shining Puni.
Found and installed all Power Reactors.
Entered the Kurken Bunker.
Saved the goat you met on your travels.
Created the Bomb Rod.
Installed the Multiplicauldron at the secret hideout.
Visited the Holy Tower of Pynnor and learn the truth.
Helped create Rasen Pudding.
Helped Empel regain his former strength.
Spent the night camping in the Underworld.
Laid eyes on the Underworld.
Installed the Gathering Synthesizer at the secret hideout.
Learned about the history of Ryza and the others.
Created the Bug Net.
Installed a Power Reactor at the secret hideout.
Defeated the dragon at the old castle.
Found one treasure chest.
Created the Hammer.
Created the Fishing Rod.
Built a secret hideout for everyone.
Witnessed the rise of a strange beast.
Attended a tea party with Ryza and Klaudia.
Created the Woodcutter's Axe.
Created the Reaper's Scythe.
Synthesized for the first time.
Visited the mainland for the first time.
Earned all trophies.
Got Ryza's battle level to 50.
Became a Braver.
Activated everyone's Fatal Drive.
Created a bottle with Gathering Synthesizer Level 51.
Defeated the Queen of Shadows.