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