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