OK, here goes... this story was not what I would normally go for (there I said it - and given I won this in a competition it seems a bit ungrateful to do so) having said that, the imagery was good and the mythology seemed well thought out and developed for a short story. It did feel half-way through that it was a shortened version or a concept for a longer work, which it could easily have become; and I think that coloured my expectations. The nature (no pun intended) of the portal fed into the story concept, a feature lacking in many portal stories (especially short ones).
The themes worked well, as a story set with an ecology point to make the message came across and thus the point was made.
I leave it to the mind of the reader as to whether my next comment is a criticism or a compliment...
Why wasn't this a novel? The potential in the story and the writing was there. The intro to the world needs only a little fleshing and it could easily be a good few chapters. A bit more intro to Max (and the talent is there) in our world and that's a chapter at least.
Unfair for a short story? Probably. Unfair as to the talent available to the writer? No. Unfair as to the potential of the story to be so much more? Hell, no.
Sorry Hannah