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