Here is the full list of all 21 Dungeonmans achievements.
Turned down an invitation to a Super Awesome Monster Party
Turn in your first Proof of Stremf
Turn in 50 Proofs of Stremf to the same Academy
Turn in 500 Proofs of Stremf to the same Academy and unlock the Battlemaster sprite
Use Xespera's Challenge on your first turn in a Super Awesome Monster Party
Defeat a Dance Commander
Recover from critical health with a bite of Flavorful Pre-Baconized Bacon
Fully evolve the Academy Alchemy Lab and unlock the Grand Chemistress sprite.
Fully evolve the Academy Library and unlock the High Libromancer Straum sprite
Kill 30 enemies within the lifespan of a single Mostly
Upgrade the Academy Alchemy Lab and Library at least once, unlock the Museum, and turn in a Proof of Stremf
Create a brand new Academy and defeat the final boss with your first graduate. No deaths!
Discover the secret location of the Dread Spire
Defeat Final Foom and complete the Dungeonmans campaign
Called forth your tiny crimson vassals to die in battle
Careful, o Dungeonmans...
Unlocked Amaranth Pandemonium. Have fun!
Pick up a Legendary item
Learn 20 points worth of masteries on a single hero, including the 5 you started with
Learn 30 points worth of masteries on a single hero
Learn 40 points worth of masteries on a single hero