Here is the full list of all 60 Legend of Grimrock 2 achievements.
Summon the Viper Roots in under 6 minutes
Find all secrets
Dig up all treasure chests
Defeat a monster with a backstab attack
Collect and wear full set of Crystal armor (6 pieces)
Collect and wear archmage's uniform (4 pieces)
Collect and wear full set of Meteor armor (6 pieces)
Find the pie
Learn 15 spells
Enter the Nexus
Visit all levels
Enter the Shrine of Balance
Defeat the Lindworm
Max out three skills
Find 8 skulls
Enter the Castle
Collect four elemental essences
Defeat the Wormbound brothers
Find Bane
Polymorph 10 times
Open the gate to the Cemetery
Assemble the Meteor Hammer
Find 50 secrets
Enter the Crystal Mines
Find the Relic
Dig up three treasure chests
Defeat the Ratling Boss
Catch 25 fish
Collect and wear rogue's wardrobe (5 pieces)
Open the door to the Archives
Mix a total of 50 potions
Perform 500 missile or throwing weapon attacks
Perform 100 power attacks
Find 25 secrets
Cast 500 spells
Open 5 gold locks
Defeat a Magma Golem
Kill a monster with a single blow
Kill 250 monsters
Enter the Pyramid of Umas
Travel 10000 tiles
Kill a monster by teleporting on it
Defeat Herder's Den
Cast 250 Spells
Dive 250 tiles
Visit 10 levels
Collect an elemental essence
Max out a skill
Defeat the Summon Stones
Kill a monster by throwing pants at it
Deal a killing blow with unarmed attack
Find 10 secrets
Perform 500 melee weapon attacks
Mix a total of 10 potions
Defeat the Viper Roots
Cast 25 spells
Complete the game with hard difficulty setting
Complete the game with old school mode
Reach level 10 with a farmer
Complete the game with Ironman and Single-use Crystals modes turned on