Full list of all 96 UnderMine achievements.
The base game contains 94 achievements, and there is 1 DLC pack containing 2 achievements.
Fully upgraded the bombs
Crafted 10 new potions
Fully expanded the potion slots
Defeated Selt, Mortar, and Noori with the same peasant
Fully upgraded the tunic
Crafted 30 new relics
Bought every item in a fully expanded shop
Died 50 times
Entered the Golden Core before defeating Ponzu
Completely expanded the Pilfer shop
Fully upgraded the gloves
Discovered the Othermine
Fully upgraded the pickaxe
Lifted the Summoning Stone for the first time
Defeated Seer, World's Heart
Lost 5,000 gold to pilfers
Expanded the potion slot once
Entered the Golden Core
Defeated Ponzu, Scaled Assembly
Healed 1,000 hp using food in one run
Peeped 100 skeletons
Crafted 20 new relics
Had 6 curses active at the same time
Thwarted 500 pilfers
Fully upgraded the goldsack
Fully upgraded the counter weight
Completely expanded Dibble's shop
Defeated Noori, Spectre of Darkness
Spent 100,000 gold at shops
Found all 3 dogs in the UnderMine
Rescued Kurtz
Entered the Shimmering Caverns
Spent 50,000 gold at shops
Crafted 10 new relics
Learned a new blessing
Crafted a new potion
Stole an item from the shop
Had something popcorn 5 times in a row
Spent 10,000 gold at shops
Entered the Halls of Din
Defeated Mortar, Charged Golem
Died 10 times
Put yourself out in water
Rescued Lillyth
Crafted a new relic
Defeated the Dungeon Gargoyles
Peeped 10 skeletons
Rescued Dibble
Entered the Delvemore Dungeon
Joined the Pilfer Loyalty Program
Defeated Selt, Lord of Sand
Assisted Beltrame
Ate cooked food for the first time
Defeated a Hoarding Pilfer
Destroyed 20 signs
Met Black Rabbit
Discovered a secret floor
Cleansed a curse for the first time
Rescued Dodson
Defeated the Rockpile Mimic
Rescued Wayland
Discovered a secret room
Entered the Delvemore Dungeon before defeating Selt
Entered the Halls of Din before defeating Mortar
Learned 10 new blessings
Died 100 times
Held 99 keys at once
Held 99 bombs at once
Discovered the Golden Idol
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
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