Here is the full list of all 15 One More Dungeon achievements.
Сomplete the game with "Fog" or "Broken cartridge" mutator
Сomplete the game with "No margin for error" or "Curse" mutator
Put the items in all the inventory slots
Buy all the mutators
Finish the level in under 2 minutes
Spend 50 coins
Сomplete eight levels
Сomplete the game
Kill the Ancient Necromancer
Die after drinking the poison
Сomplete five levels
Kill the Elder Flower
Squash 25 bugs
Start the game with any mutator
Сomplete the first level