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