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