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.
Find an epic-quality weapon.
Slay the Demiurge.
Tis this a demon?
Enter into the Dark World.
Destroy the Soul Collector.
Face The Eater!
She rules an army of beasts in the Black Church, defeat The Yaldabaoth.
Slayed the Fiend.
Slay the Fire Nob Glob.
Kill the leader of the Thief Kings, The Cursed Wizard!
Kill the king of Skeletons.
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.