Here is the full list of all 15 bit Dungeon II achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Find an epic-quality weapon.
Free the ghost from her grave.
Slay the Demiurge.
Tis this a demon?
Enter into the Dark World.
Slay the Fire Nob Glob.
Kill the king of Skeletons.
Slayed the Fiend.
You have died. You have all lost things. You can not take your possessions with you to the next incarnation.
Face The Eater!
She rules an army of beasts in the Black Church, defeat The Yaldabaoth.
Kill the leader of the Thief Kings, The Cursed Wizard!
Destroy the Soul Collector.
Kill a mini-boss.
Reach level ten.