Here is the full list of all 21 Etrian Odyssey II HD achievements.
Defeated a boss in a single turn.
Reached the Sixth Stratum.
Defeated the Overlord.
Reached the Fifth Stratum.
Reached the Fourth Stratum.
Dealt 1,000 damage with a single hit.
Reached the Third Stratum.
Unlocked the Beast class.
Reached the Second Stratum.
Encountered an enemy through mining ore, gathering plants, or chopping wood.
Reached the First Stratum.
Obtained all other achievements.
Defeated the boss of the Sixth Stratum on Expert difficulty.
Defeated the Ur-Child.
Retired an adventurer.
Let an adventurer rest.
Obtained more than 250,000 Ental.
Completed the quest "The beautiful Queen".
Defeated the Wyrm.
Defeated the Drake.
Defeated the Dragon.