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