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