Here is the full list of all 24 The World Next Door achievements.
Make your way back to the portal.
Defeat Cenoba and complete the Celestial Shrine.
Cast 30 Strike spells in a single play-through.
Cast 30 Ember spells in a single play-through.
Cast 30 Void spells in a single play-through.
Cast 30 Cure spells in a single play-through.
Cast 30 Shock spells in a single play-through.
Defeat Breccio and complete the Forge Shrine.
Defeat Zona & Addie and complete the Undercroft Shrine.
Defeat The Mongrel and complete the Channel Shrine.
Defeat Cornell and learn the truth about Jun's past.
Use the Weird Sword to open the portal and return to Earth.
Complete all empowering puzzles in a single play-through.
Summon all your friends into battle at least once in a single play-through.
Find every item in the game in a single play-through.
Complete the quest "Horace's Training Camp."
Complete the quest "A Research Expedition."
Complete the quest "Emrys Academia."
Complete the quest "The Missing Manga."
Complete the quest "Pretty in Pink."
Complete the quest "The Mysterious Locket."
Complete the quest "The Secret Letter."
Complete the quest "Sports and Superstitions."
Cast 15 Essence spells in a single play-through.