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