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