Short film - developed idea

I have developed my short film idea further. I now have the full story and an idea of what I want it to look like.

STORY/SCENES
The film starts with a close up of a girl's eyes. As the camera zooms out slowly, flashbacks are shown of the girl with a boy, playing and messing around in a park. The flashbacks continue, ending with the boy pulling a funny face at the camera. When the flashbacks end, the camera is zoomed out to its fullest showing the girl sitting on a bed with blood on her hands. A door is opened downstairs and a woman can be heard saying, 'Dinner's ready love.' The girl turns her head towards the door and shouts, 'Coming Mum'. As she stands, the boy can be seen lying on the bed covered in blood. As the bedroom door closes, a shot of the boy and girl smiling at the camera appears. This fades to black and the credits roll.

REPRESENTATION
In my short film, I want to challenge the representation of women in horror films. They are shown as weak and an easy target for the villain. In some films, they are represented as being dumb and are often killed early on. This representation is being challenged more and more by film-makers, with females being shown as being more independent and able to fight back. From the 1978 film, Halloween where Jamie Lee Curtis defeats Michael Myers on numerous occasions, to Neve Campbell in the Scream films killing the murderer throughout the series.
Another representation I want to challenge from the horror genre is that of the bad guy. They tend to be almost monstrous and generally rooted in fiction. For my short film, I want to take a lead from films such as Eden Lake where the villians were a group of youths and thus were purely human. By having the girlfriend as a killer in my film, I want to make the audience think about threats being much closer to home than the majority of horror films make out. I hope this will enhance the fear factor of my short film.
Here is the trailer for Eden Lake which includes a few clips from the ending of the film -


Eden Lake (2008) Trailer from dave smith on Vimeo.

*UPDATE*
After filming, some of the representations within my film have changed slightly. In the original post, I talked about how having the girlfriend as the killer would bring a more human aspect to the idea of the villain. Whilst the killer is still the same character, she is no longer 'human'. I hope to retain the idea of humanity however by focusing on her reactions.