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