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