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