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