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.
Face The Eater!
Slayed the Fiend.
She rules an army of beasts in the Black Church, defeat The Yaldabaoth.
Destroy the Soul Collector.
Kill the leader of the Thief Kings, The Cursed Wizard!
Kill the king of Skeletons.
Slay the Fire Nob Glob.
Kill a mini-boss.
Reach level ten.
You have died. You have all lost things. You can not take your possessions with you to the next incarnation.