Here is the full list of all 51 Instant Dungeon! achievements.
Rescue 25 friends in Rescue Relish
Kill 25 Wraiths
Die 50 times
Break 50 shields
Complete 50 quests in Adventure Mix
Break 50 helemts
Survive to Round 15 in Maxima Mash
Use 50 time freeze spells
Kill 2 monsters with one frozen monster
Throw 10 weapons at boss monsters
Freeze 25 monsters
Use 50 crystal balls
Cast 50 fireball spells
Kill 500 monsters
Kill 3 monsters with 1 axe
Kill 25 Cyclops
Pick up 100 diamonds
Reach Level 10 in Soul Succor
Kill 3 monsters with one lightning spell
Reach Level 15 in Dark Roast
Use 50 light spells
Reach Level 50 in any game flavor
Reach Round 10 in Practice Formula
Kill 100 Skeletons
Reach Level 12 in Boss Blend
Survive the Wizard in Action Recipe
Escape the Stone Giants in Action Recipe
Light 50 torches
Kill a monster with a frozen monster
Kill 25 monsters with pumpkin bombs
Exit the lair of the Blue Dragon in Action Recipe
Axe 10 monsters in the back
Reach Level 30 in Weak Sauce
Kill a Pumpkin Demon with a pumpkin bomb
Sneak past the Pumpkin Master in Action Recipe
Pick up 1000 treasures
Stab 10 monsters in the back with a knife
Throw 50 knives
Kill monsters with both sides of one fireball spell
Kill 50 monsters
Kill 2 monsters with 1 axe
Kill 25 Skeletons
Dodge the Dracolich in Action Recipe
Throw a weapon at a boss
Escape from the Red Dragon in Action Recipe
Kill a monster
Pick up a treasure
Pick up 10,000 treasures
Kill 100 Cyclops
Kill 100 Wraiths
Reach Level 24 in Boss Blend