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