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