Here is the full list of all 69 Angel Wings achievements.
Complete all routes
Complete the band
Enter the drum studio
Receive the sheet music
Unlock Chaeng's Good Ending
Unlock Chaeng's Medium Ending
Unlock all Chaeng outfits
Unlock all outfits
Unlock Seola's Good Ending
Unlock Seola's Medium Ending
Unlock all Seola outfits
Defeat Kaori
Play video games together
Complete the lake run
Stick around for extra practice
Leave class early
Unlock Nuri's Medium Ending
Unlock all Nuri outfits
Unlock Hyedong's Good Ending
Fight!
Unlock Hyedong's Medium Ending
Unlock all Hyedong outfits
Jump into the hotel pool
Unlock all Yujeong outfits
Unlock Yuri's Ending
Unlock Jei's Good Ending
Tell Jei the truth
Unlock Jei's Medium Ending
Unlock all Jei outfits
Buy some food
Unlock Kei's ending
Unlock all Kei outfits
Unlock the true ending
Check the computer
Reject the current timeline
Help out with cooking
Go to the forest together
Unlock Yujeong's Good Ending
Begin a Route Selection campaign
Give Chaeng the phone
Watch drama together
Win a basketball game
Follow Jihyun
Eat chicken together
Go to the mall with Chaeng
Select the Hermit card
Unlock Yujeong's Medium Ending
Choose to help Yujeong
Eat ramen with Yujeong
Take a coffee break
Choose stealth mode
Complete an activity with Yujeong
Select the Hierophant card
Unlock Nuri's Good Ending
Complete any route
Complete the game once
Control your emotions
Go skating
Attend the work party
Party time!
Attend the beach
Eat salad together
Visit the phone shop
Complete the work assignment
Complete an activity with Seola
Enter the bar
Meet Nuri
Select the World card
Pick up the phone