Here is the full list of all 31 EvilQuest achievements.
Beat the game on Difficult
Beat the game on Normal
Equip all Chaos Gear
Eat 10 Hams and 10 Steaks
Kill 8 enemies at one time with Shadow2
Reach an Intelligence level of 35
Kill 100 Dragons
Reach a Strength level of 35
Reach a Toughness level of 35
Reach a Vitality level of 35
Eat 75 Pieces of Food
Equip The Invisibility Cloak
Equip The Amulet of Magic
Kill 1500 enemies
Kill 5 enemies at one time with Lit2
Open The Lightning Seal
Equip all Dragon Gear
Murder 5 deserving NPCs
Obtain a portrait of Galvis
Give 1000 GP to a dancer
Kill King Jerric
Kill 50 enemies with Fire2
Open The Fire Seal
Eat 3 Whole Chickens
Kill 750 enemies
Open The Ice Seal
Kill 4 enemies at one time with Earth2
Freeze 30 enemies with Ice
Open The Earth Seal
Kill King Jerric's top general
Learn Ice1 and kill your teacher