|Greetings from the Critique Club:
I didn't cast an eye over this challenge, so I look here with fresh eyes. If I'd have voted, I'd have been between 5 and 6 and settled on a 6. From your histogram I can see my response would be fairly typical of the way your image was received by the wider voting audience.
You picked up a couple of 1s, I suspect they came from members of the DNMC police who would have looked for a 'proper' horizon and not found one.
For me, I like the simplicity of the shot, it works on that level but in any photographic competition you get judged on your stand-out-from-the-crowdness and pairing a simple shot with quite a flat feel in the post processing is likely to have the opposite outcome. Here the dynamic range of the mid tones and highlights seems quite restricted, we do have deep shadows, but even these are robbed of a little detail.
Given that you did this with Silver Efex (first version), I think using a less tinted tone (the first coffee one- number 7??), moving up the highlight slider, increasing the strength of the vignette (slider down) and then removing it from her with control points and then adding some structure into her eyes, tip of nose, mouth and hands would have helped to draw the eye to her.
At the moment the higher contrast grass just ahead of her catches and pulls the eye.
I don't know if you smoothed the skin or decreased structure in the skin (or even if you used the smooth skin preset) but I always take care to preserve those areas I mention above. Dropping control points on each, brightening them and adding structure with a very small effect radius is almost a default in my work flow. With portrait work, I tend to emphasise the eyes just as much as I can without them looking like they've been processed. I don't always get in right but I'm getting better.
Overall this is a nice picture, the tilt as used makes a great contribution to the overall composition but I think your processing has placed the emphasis slightly away from where you need it to be.