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