Here is the full list of all 48 Just Deserts achievements.
Talk 50 times
Get money for the first time
Talk 300 times
Give 10 disliked items to 1 heroine in 1 game
Give 20 disliked items to 1 heroine in 1 game
Achieve "Love" relationship with all heroines in 1 game
Achieve "Infatuated" relationship with all heroines in 1 game
Reveal all character’s talk lines
Kill 30 aliens with hand gun in 1 game
Defeat 50 aliens in 1 game
Defeat 150 aliens in 1 game
Die before day 2
Use Cornelia's Spear Fall support in a battle
Use Cornelia's Spear Fall support 4 times in 1 game
Run from battle 30 times in 1 game
Use medicine 25 times in 1 game
Win 5 battles each in less than 4 turns in 1 game
Win in 1 turn, 5 times in 1 game
Give 30 packs of instant noodle
Give 30 erotic items
Buy 100 items
Buy 30 bottles of mineral water in 1 game
Buy 25 teddy bears or 25 polar bears in 1 game
Get a Lucky Pendant
Reach 1,000,000 Bz cash
Reach 5,000,000 million Bz cash
Has 0 Bz money
Sleep before night for 5 days in 1 game
Sleep in the morning for 10 days in 1 game
Sleep in the morning for 20 days in 1 game
Have a meal 30 times in 1 game
Workout 30 times in 1 game
Shooting Practice 30 times in 1 game
Swimming 30 times in 1 game
Complete 40 Patrol Works in 1 game
Complete 30 Quests in 1 game
Complete 1 game (1 route)
Complete all game routes
Passed out 10 times in 1 game
Achieve "Single" End
Achieve “Harem” End
Reveal all CG
Reveal all story
Complete Eve route
Complete Cornelia route
Complete Jennifer route
Complete Yumi route
Complete Cecile route