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