Here is the full list of all 24 Learn Japanese To Survive! Katakana War achievements.
Clear the game.
Complete all 20 side quests.
Obtain the ultimate sword.
Complete 15 side quests.
Unlock the potential of corn soup.
Complete lesson 10.
Complete lesson 9.
Maximize all character's affection levels.
Complete lesson 8.
Complete lesson 7.
Complete 10 side quests.
Complete lesson 6.
Maximize a character's affection level.
Complete lesson 5.
Visit the Challenge Castle.
Complete 5 side quests.
Complete lesson 4.
Complete lesson 3.
Try 3 different types of seafood.
View a character's affection event.
Unlock the power of the Crystarium
Complete a side quest.
Complete lesson 2.
Complete lesson 1.