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