Here is the full list of all 20 If My Heart Had Wings achievements.
Watch 40% of the cutscenes.
Fail to complete any route.
Watch 20% of the cutscenes.
Finish the common routes.
Watch the second opening movie.
Watch the first opening movie.
Watch a cutscene for the first time.
Start the game.
Watch the ending movie.
Open the gallery.
Complete the game for the first time.
Complete the Kotori route.
Complete the Amane route.
Complete the Ageha route.
Complete the Asa route.
Complete the Yoru route.
Complete all routes.
Watch 60% of the cutscenes.
Watch 80% of the cutscenes.
Watch all of the cutscenes.