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