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