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