Joshin Eishi Cryska EX ~Kisama wa, Hontou ni Saitei no Kuzu da na!~

A short visual novel from Muv Luv universe.
Alpha falls in love with her childhood friend, Eisuke. So she decides to give him a letter. But, things get complicated by not having put his name. A series of misunderstandings and some good sex make this a nice short story.