Community members on platforms like the Steam Community often shared compressed files containing translation assets to help players understand the story before the official Steam release.
The story follows Sowel Devosiana, a girl who joins the "Gun Bullet Children" program to hunt vampires and avenge her parents. eXceed.Gun.Bullet.Children.rar
You can no longer purchase it directly on Steam, though existing owners can still download it. Physical copies or keys from third-party resellers are the only remaining official ways to obtain it. Translation & Files Community members on platforms like the Steam Community
Are you trying to from that archive, or were you looking for a technical breakdown of how its bullet patterns work? Gun Bullet Children | EXceed Wiki | Fandom Physical copies or keys from third-party resellers are
The .rar file you mentioned likely contains either a pirated copy of the game or, more commonly, an for the original Japanese retail version.