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