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