Full list of all 96 UnderMine achievements.
The base game contains 94 achievements, and there is 1 DLC pack containing 2 achievements.
Lifted the Summoning Stone 30 times
Completed an Othermine run without upgrades from the antechamber chest or shops
Completed 3 runs of Othermine without dying
Defeated Seer, World's Heart without upgrades
Defeated Ponzu, Scaled Assembly without upgrades
Defeated Noori, Spectre of Darkness without upgrades
Defeated Mortar, Charged Golem without upgrades
Defeated Selt, Lord of Sand without upgrades
Completed a run of the Othermine
Spawned a secret shop, in a secret shop, in a secret shop
Died 100 times
Died with an Elixir in your inventory
Held 99 keys at once
Held 99 bombs at once
Lifted the Summoning Stone 10 times
Transmuted 3 Relics at the same time using Transmutagen
Rescued Kurtz
Bought every item in a fully expanded shop
Found all 3 dogs in the UnderMine
Crafted 30 new relics
Fully upgraded the bombs
Completely expanded the Pilfer shop
Died 50 times
Entered the Halls of Din before defeating Mortar
Discovered the Golden Idol
Peeped 100 skeletons
Fully expanded the potion slots
Fully upgraded the gloves
Fully upgraded the tunic
Defeated Selt, Mortar, and Noori with the same peasant
Completely expanded Dibble's shop
Fully upgraded the pickaxe
Discovered the Othermine
Lifted the Summoning Stone for the first time
Defeated Seer, World's Heart
Defeated Ponzu, Scaled Assembly
Held 3 of the same potion at the same time
Defeated a Hoarding Pilfer
Had 6 curses active at the same time
Thwarted 500 pilfers
Crafted 20 new relics
Fully upgraded the goldsack
Learned a new blessing
Learned 10 new blessings
Spent 100,000 gold at shops
Healed 1,000 hp using food in one run
Spent 50,000 gold at shops
Fully upgraded the counter weight
Lost 5,000 gold to pilfers
Entered the Golden Core
Entered the Golden Core before defeating Ponzu
Defeated Noori, Spectre of Darkness
Crafted 10 new potions
Entered the Shimmering Caverns
Stole an item from the shop
Crafted 10 new relics
Rescued Lillyth
Had something popcorn 5 times in a row
Defeated the Dungeon Gargoyles
Spent 10,000 gold at shops
Defeated Selt, Lord of Sand
Crafted a new potion
Entered the Halls of Din
Defeated Mortar, Charged Golem
Expanded the potion slot once
Rescued Dibble
Peeped 10 skeletons
Crafted a new relic
Joined the Pilfer Loyalty Program
Assisted Beltrame
Died 10 times
Destroyed 20 signs
Entered the Delvemore Dungeon
Entered the Delvemore Dungeon before defeating Selt
Ate cooked food for the first time
Discovered a secret floor
Met Black Rabbit
Rescued Dodson
Defeated the Rockpile Mimic
Cleansed a curse for the first time
Put yourself out in water
Discovered a secret room
Rescued Wayland
Completed a run with at least 2 hexes