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