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