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