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