Here is the full list of all 69 Diehard Dungeon achievements.
Attain Fighter rank.
Attain Warrior rank.
Attain Valiant rank.
Attain Adept rank.
Attain Slayer rank.
Attain Hero rank.
Attain Champion rank.
Attain Legend rank.
Attain Diehard rank.
Open the gold chest.
Escape the dungeon.
Defeat the Dungeon Master.
Escape the dungeon in Champion Mode.
The Companion Chest upgrades to its maximum level.
Win a Trapdoor game.
Use 20 Teleporters.
Obtain Houdini ability.
Obtain Heartbreaker ability.
Obtain Dash ability.
Obtain Slash ability.
Obtain Toasty ability.
Obtain Kaboom ability.
Obtain Scatter ability.
Obtain Knives ability.
Obtain Voodoo ability.
Obtain Fireproof ability.
Obtain Iron Grip ability.
Obtain Mithridate ability.
Obtain Lightfoot ability.
Obtain Trigger Happy ability.
Obtain Forget-Me-Not ability.
Obtain Looter ability.
Obtain Heavy Duty ability.
Obtain Triple Shot ability.
Obtain Repel ability.
Obtain Courage ability.
Defeat Mr Illusion.
Defeat Stumpy.
Defeat Evil Chest.
Defeat Hive Mind.
Defeat Zombie Chest.
Defeat Giant Oaf.
Defeat 2000 enemies.
Collect 10,000 treasure.
Have 20 tokens.
Pickup 100 hearts.
Destroy 300 lights.
Avoid opening 10 chests.
Avoid picking up 20 hearts.
Destroy 20 chests.
Achieve rank 10 in Mayhem.
Use 50 tokens.
Destroy 1000 containers.
Defeat 200 enemies by setting them on fire.
Destroy 500 containers with fire.
Survive 20 rooms of Survival
Obtain Sense ability.
Obtain Vision ability.
Obtain Attract ability.
Obtain Reflex ability.
Obtain Pierce ability.
Escape the dungeon at Diehard rank, in Champion Mode, and defeat the Dungeon Master.
Complete Fading Light in under 3 minutes.