Shinsei Kourin Dacryon ~Tadashii Tenshi no Sodatekata~

Sana Aiba is a bright and cheerful school girl that just transferred to Etoile Academy.
On her first day a the academy she quickly becomes friends with Mei Kanbara, a shy but kind girl who attends the same class and sits next to her.
On their way home, Mei tells Sana about a portable videogame called "Angel Maker", she received the videogame by mail from a magazine and they sent her a second copy by mistake, so she decides to gift one copy to Sana to celebrate their friendship.
The two girls activate the videogames, but to their suprise the little angel creatures they are supposed to help grow in the game appear before them.
"Protect us, help us grow, and in exchange we'll give you fantastical powers!"
Right at that moment the two girls are attacked by hideous monsters...