Constructive criticism?

So, I wrote a piece fairly recently. I say recently, I mean I finished it recently. I have a habit of taking ages to finish even short pieces. If you guys get a moment, it'd be great if you could read it.

I've had mixed responses, though all positive, and I'm pretty sure there are negatives and having seen a comment a friend got on one of his stories (brok3n_butterfly) I'd love to see that kind of constructive criticism on one of my own.

It's called Flash, and you'll find it here:
http://gyllybug.deviantart.com/#/d418oec

Thanks!