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