Full list of all 101 Skul: The Hero Slayer achievements.
The base game contains 57 achievements, and there are 5 DLC packs containing 44 achievements.
Restore the Demon King Castle to its original form
Acquire Gold Gargoyle
Acquire Sniper
Acquire Ghoooooul
Acquire Magnifico
Acquire Dark Alchemist
Acquire Minotaurus III
Defeat the First Hero without getting hit
Acquire Frozen Spirit
Acquire Demolitions Expert
Acquire Neo Samurai
Acquire Super Rock Star
Acquire Joker
Defeat St. Joan II without getting hit
Defeat Chimaera without getting hit
Defeat the Leiana Sisters without getting hit
Acquire Master Ninja
Acquire Nightmare
Acquire Poseidon
Acquire Eternal Werewolf
Kill 100 adventurers
Acquire Warlord
Acquire Devil Berserker
Defeat the First Hero as Little Bone
Acquire Dark Avenger
Acquire Abyssal Monarch
Acquire Yaksha
Defeat the First Hero without saving the stage NPC
Acquire Elder Ent Skull
Acquire Eternal Mummy
Acquire Desperado
Acquire Soul Knight
Acquire Carleon Commander
Defeat Yggdrasil without getting hit
Acquire Royal Guard Captain
Keep talking to Headless
Play on Rookie Mode
Keep restocking from the collector
Acquire Defender Captain
Acquire Gambler
Rescue the Demon King and return to the Demon King Castle
Stay in the black market for 5 minutes
Reach the top of the chandelier in the Demon King Castle
Defeat the Sword of Carleon, the First Hero
Acquire Vanguard Captain
Defeat the archbishop of the Leonia Order, St. Joan II
Defeat the distorted goddess, Chimaera
Acquire Destroyer
Reach the top of the throne in the Demon King Castle
Defeat the adjutants of the Gold Mane Knights, the Leiana Sisters
Acquire Champion
Acquire Grim Reaper
Defeat the elder ent, Yggdrasil
Die from a trap
Acquire Arch Lich
Stay in the black market for 1 minute
Return after experiencing death