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