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