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