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.
Try 3 different types of seafood.
Complete 15 side quests.
Maximize all character's affection levels.
Complete lesson 10.
Unlock the potential of corn soup.
Complete lesson 9.
Complete 10 side quests.
Complete lesson 8.
Maximize a character's affection level.
Complete lesson 7.
Complete lesson 6.
Visit the Challenge Castle.
Complete lesson 5.
Unlock the power of the Crystarium
Complete 5 side quests.
Complete lesson 4.
Complete lesson 3.
View a character's affection event.
Complete a side quest.
Complete lesson 2.
Complete lesson 1.