Here is the full list of all 18 Queen's Quest 3: The End of Dawn achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Defeat the Dragon Lord.
Finish every the Mini-games without skipping any of them.
Destroy the machine powering the crystal.
Finish every Hidden Object Scenes without using a hint.
Find every Collectable.
Complete the ritual.
Complete a Hidden Object Scene in less than one minute.
Complete three Hidden Object Scenes in less than 10 minutes.
Complete a Hidden Object Scenes without mistake.
Return the crystals to the witch.
Find 3 hidden objects in three seconds.
Find 30 Collectables.
Find the Dragon Crystals.
Open the library.
Complete five Mini-games without skipping them.
Complete a Mini-game in less than one minute.
Complete a Hidden Object Scene without using a hint.
Find one Collectable.