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