Here is the full list of all 15 Dungeon Arsenal achievements.
Complete the Relicarium.
Unlock all characters.
Finish the game on Easy Mode.
Finish the game on Normal Mode.
Finish the game on Hard Mode.
Collect 10,000 Gold in total.
Destroy 250 Monsters.
Open 20 treasure chests.
Spend 500 AP in total.
Finish the game on Normal or Hard Mode without acquiring any Relics.
Finish the game on Insane Mode.
Finish the game on Insane Mode without acquiring any Relics.